Chapter 30. Aggregating Container Logs

30.1. Overview

As an OpenShift Container Platform cluster administrator, you can deploy the EFK stack to aggregate logs for a range of OpenShift Container Platform services. Application developers can view the logs of the projects for which they have view access. The EFK stack aggregates logs from hosts and applications, whether coming from multiple containers or even deleted pods.

The EFK stack is a modified version of the ELK stack and is comprised of:

Elasticsearch (ES): An object store where all logs are stored.
Fluentd: Gathers logs from nodes and feeds them to Elasticsearch.
Kibana: A web UI for Elasticsearch.

Once deployed in a cluster, the stack aggregates logs from all nodes and projects into Elasticsearch, and provides a Kibana UI to view any logs. Cluster administrators can view all logs, but application developers can only view logs for projects they have permission to view. The stack components communicate securely.

Aggregated logging is supported using the json-file or journald driver in Docker. The Docker log driver is set to journald as the default for all nodes. See Updating Fluentd’s Log Source After a Docker Log Driver Update for more information about switching between json-file and journald. Fluentd automatically determines which log driver (journald or json-file) the container runtime is using.

When the log driver is set to journald, Fluentd reads journald logs. When set to json-file Fluentd reads from /var/log/containers.

See Managing Docker Container Logs for information on json-file logging driver options to manage container logs and prevent filling node disks.

Important

If Docker log-driver is set to journald, there is no log rate throttling with the journald driver. As a result, there is a risk of denial-of-service attacks from rogue containers.

30.2. Pre-deployment Configuration

An Ansible playbook is available to deploy and upgrade aggregated logging. You should familiarize yourself with the advanced installation and configuration section. This provides information for preparing to use Ansible and includes information about configuration. Parameters are added to the Ansible inventory file to configure various areas of the EFK stack.
Review the sizing guidelines to determine how best to configure your deployment.
Ensure that you have deployed a router for the cluster.
Ensure that you have the necessary storage for Elasticsearch. Note that each Elasticsearch replica requires its own storage volume. See Elasticsearch for more information.
Choose a project. Once deployed, the EFK stack collects logs for every project within your OpenShift Container Platform cluster. The examples in this section use the default project logging. The Ansible playbook creates the project for you if it does not already exist. You will only need to create a project if you want to specify a node-selector on it. Otherwise, the openshift-logging role will create a project.
```
$ oc adm new-project logging --node-selector=""
$ oc project logging
```
Note
Specifying an empty node selector on the project is recommended, as Fluentd should be deployed throughout the cluster and any selector would restrict where it is deployed. To control component placement, specify node selectors per component to be applied to their deployment configurations.

30.3. Specifying Logging Ansible Variables

Parameters for the EFK deployment may be specified to the inventory host file to override the defaults. Read the Elasticsearch and the Fluentd sections before choosing parameters:

Note

By default the Elasticsearch service uses port 9300 for TCP communication between nodes in a cluster.

Parameter	Description
`openshift_logging_image_prefix`	The prefix for logging component images. For example, setting the prefix to registry.access.redhat.com/openshift3/ creates registry.access.redhat.com/openshift3/logging-fluentd:latest.
`openshift_logging_image_version`	The version for logging component images. For example, setting the version to v3.7 creates registry.access.redhat.com/openshift3/logging-fluentd:v3.7.
`openshift_logging_use_ops`	If set to `true`, configures a second Elasticsearch cluster and Kibana for operations logs. Fluentd splits logs between the main cluster and a cluster reserved for operations logs, which consists of the logs from the projects default, openshift, and openshift-infra, as well as Docker, OpenShift, and system logs from the journal. This means a second Elasticsearch cluster and Kibana are deployed. The deployments are distinguishable by the -ops suffix included in their names and have parallel deployment options listed below and described in Creating the Curator Configuration.
`openshift_logging_master_url`	The URL for the Kubernetes master, this does not need to be public facing but should be accessible from within the cluster. For example, https://<PRIVATE-MASTER-URL>:8443.
`openshift_logging_master_public_url`	The public facing URL for the Kubernetes master. This is used for Authentication redirection by the Kibana proxy. For example, https://<CONSOLE-PUBLIC-URL-MASTER>:8443.
`openshift_logging_namespace`	The namespace where Aggregated Logging is deployed.
`openshift_logging_install_logging`	Set to `true` to install logging. Set to `false` to uninstall logging.
`openshift_logging_purge_logging`	The common uninstall keeps PVC to prevent unwanted data loss during reinstalls. To ensure that the Ansible playbook completely and irreversibly removes all logging persistent data including PVC, set `openshift_logging_install_logging` to 'false' to trigger uninstallation and `openshift_logging_purge_logging` to 'true'. The default is set to 'false'.
`openshift_logging_install_eventrouter`	Coupled with `openshift_logging_install_logging`. When both are set to 'true', eventrouter will be installed. When both are 'false', eventrouter will be uninstalled.
`openshift_logging_eventrouter_image_prefix`	The prefix for the eventrouter logging image. The default is set to `openshift_logging_image_prefix`.
`openshift_logging_eventrouter_image_version`	The image version for the logging eventrouter. The default is set to 'latest'.
`openshift_logging_eventrouter_sink`	Select a sink for eventrouter, supported `stdout` and `glog`. The default is set to `stdout`.
`openshift_logging_eventrouter_nodeselector`	A map of labels, such as `"node":"infra"`,`"region":"west"`, to select the nodes where the pod will land.
`openshift_logging_eventrouter_replicas`	The default is set to '1'.
`openshift_logging_eventrouter_cpu_limit`	The minimum amount of CPU to allocate to eventrouter. The default is set to '100m'.
`openshift_logging_eventrouter_memory_limit`	The memory limit for eventrouter pods. The default is set to '128Mi'.
`openshift_logging_eventrouter_namespace`	The project where eventrouter is deployed. The default is set to 'default'. Important Do not set the project to anything other than `default` or `openshift-*`. If you specify a different project, event information from the other project can leak into indices that are not restricted to operations users. To use a non-default project, create the project as usual using `oc new-project`.
`openshift_logging_image_pull_secret`	Specify the name of an existing pull secret to be used for pulling component images from an authenticated registry.
`openshift_logging_curator_default_days`	The default minimum age (in days) Curator uses for deleting log records.
`openshift_logging_curator_run_hour`	The hour of the day Curator will run.
`openshift_logging_curator_run_minute`	The minute of the hour Curator will run.
`openshift_logging_curator_run_timezone`	The timezone Curator uses for figuring out its run time. Provide a the timezone as a string in the tzselect(8) or timedatectl(1) "Region/Locality" format, for example `America/New_York` or `UTC`.
`openshift_logging_curator_script_log_level`	The script log level for Curator.
`openshift_logging_curator_log_level`	The log level for the Curator process.
`openshift_logging_curator_cpu_limit`	The amount of CPU to allocate to Curator.
`openshift_logging_curator_memory_limit`	The amount of memory to allocate to Curator.
`openshift_logging_curator_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Curator instances.
`openshift_logging_curator_ops_cpu_limit`	Equivalent to `openshift_logging_curator_cpu_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_curator_ops_memory_limit`	Equivalent to `openshift_logging_curator_memory_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_hostname`	The external host name for web clients to reach Kibana.
`openshift_logging_kibana_cpu_limit`	The amount of CPU to allocate to Kibana.
`openshift_logging_kibana_memory_limit`	The amount of memory to allocate to Kibana.
`openshift_logging_kibana_proxy_debug`	When `true`, set the Kibana Proxy log level to DEBUG.
`openshift_logging_kibana_proxy_cpu_limit`	The amount of CPU to allocate to Kibana proxy.
`openshift_logging_kibana_proxy_memory_limit`	The amount of memory to allocate to Kibana proxy.
`openshift_logging_kibana_replica_count`	The number of replicas to which Kibana should be scaled up.
`openshift_logging_kibana_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Kibana instances.
`openshift_logging_kibana_env_vars`	A map of environment variables to add to the Kibana deployment configuration. For example, {"ELASTICSEARCH_REQUESTTIMEOUT":"30000"}.
`openshift_logging_kibana_key`	The public facing key to use when creating the Kibana route.
`openshift_logging_kibana_cert`	The cert that matches the key when creating the Kibana route.
`openshift_logging_kibana_ca`	Optional. The CA to goes with the key and cert used when creating the Kibana route.
`openshift_logging_kibana_ops_hostname`	Equivalent to `openshift_logging_kibana_hostname` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_cpu_limit`	Equivalent to `openshift_logging_kibana_cpu_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_memory_limit`	Equivalent to `openshift_logging_kibana_memory_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_proxy_debug`	Equivalent to `openshift_logging_kibana_proxy_debug` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_proxy_cpu_limit`	Equivalent to `openshift_logging_kibana_proxy_cpu_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_proxy_memory_limit`	Equivalent to `openshift_logging_kibana_proxy_memory_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_kibana_ops_replica_count`	Equivalent to `openshift_logging_kibana_replica_count` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_allow_external`	Set to `true` to expose Elasticsearch as a reencrypt route. Set to `false` by default.
`openshift_logging_es_hostname`	The external-facing hostname to use for the route and the TLS server certificate. The default is set to `es`. For example, if `openshift_master_default_subdomain` is set to `=example.test`, then the default value of `openshift_logging_es_hostname` will be `es.example.test`.
`openshift_logging_es_cert`	The location of the certificate Elasticsearch uses for the external TLS server cert. The default is a generated cert.
`openshift_logging_es_key`	The location of the key Elasticsearch uses for the external TLS server cert. The default is a generated key.
`openshift_logging_es_ca_ext`	The location of the CA cert Elasticsearch uses for the external TLS server cert. The default is the internal CA.
`openshift_logging_es_ops_allow_external`	Set to `true` to expose Elasticsearch as a reencrypt route. Set to `false` by defaut.
`openshift_logging_es_ops_hostname`	The external-facing hostname to use for the route and the TLS server certificate. The default is set to `es-ops`. For example, if `openshift_master_default_subdomain` is set to `=example.test`, then the default value of `openshift_logging_es_ops_hostname` will be `es-ops.example.test`.
`openshift_logging_es_ops_cert`	The location of the certificate Elasticsearch uses for the external TLS server cert. The default is a generated cert.
`openshift_logging_es_ops_key`	The location of the key Elasticsearch uses for the external TLS server cert. The default is a generated key.
`openshift_logging_es_ops_ca_ext`	The location of the CA cert Elasticsearch uses for the external TLS server cert. The default is the internal CA.
`openshift_logging_fluentd_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Fluentd instances. Any node where Fluentd should run (typically, all) must have this label before Fluentd is able to run and collect logs. When scaling up the Aggregated Logging cluster after installation, the `openshift_logging` role labels nodes provided by `openshift_logging_fluentd_hosts` with this node selector. As part of the installation, it is recommended that you add the Fluentd node selector label to the list of persisted node labels.
`openshift_logging_fluentd_cpu_limit`	The CPU limit for Fluentd pods.
`openshift_logging_fluentd_memory_limit`	The memory limit for Fluentd pods.
`openshift_logging_fluentd_journal_read_from_head`	Set to `true` if Fluentd should read from the head of Journal when first starting up, using this may cause a delay in ES receiving current log records.
`openshift_logging_fluentd_hosts`	List of nodes that should be labeled for Fluentd to be deployed. The default is to label all nodes with ['--all']. The null value is `openshift_logging_fluentd_hosts={}`. To spin up Fluentd pods update the daemonset’s `nodeSelector` to a valid label. For example, ['host1.example.com', 'host2.example.com'].
`openshift_logging_fluentd_audit_container_engine`	When `openshift_logging_fluentd_audit_container_engine` is set to `true`, the audit log of the container engine is collected and stored in ES. Enabling this variable allows the EFK to watch the specified audit log file or the default `/var/log/audit.log` file, collects audit information for the container engine for the platform, then puts it into Kibana.
`openshift_logging_fluentd_audit_file`	Location of audit log file. The default is `/var/log/audit/audit.log`. Enabling this variable allows the EFK to watch the specified audit log file or the default `/var/log/audit.log` file, collects audit information for the container engine for the platform, then puts it into Kibana.
`openshift_logging_fluentd_audit_pos_file`	Location of the Fluentd `in_tail` position file for the audit log file. The default is `/var/log/audit/audit.log.pos`. Enabling this variable allows the EFK to watch the specified audit log file or the default `/var/log/audit.log` file, collects audit information for the container engine for the platform, then puts it into Kibana.
`openshift_logging_es_host`	The name of the ES service where Fluentd should send logs.
`openshift_logging_es_port`	The port for the ES service where Fluentd should send logs.
`openshift_logging_es_ca`	The location of the CA Fluentd uses to communicate with `openshift_logging_es_host`.
`openshift_logging_es_client_cert`	The location of the client certificate Fluentd uses for `openshift_logging_es_host`.
`openshift_logging_es_client_key`	The location of the client key Fluentd uses for `openshift_logging_es_host`.
`openshift_logging_es_cluster_size`	Elasticsearch replicas to deploy. Redundancy requires at least three or more.
`openshift_logging_es_cpu_limit`	The amount of CPU limit for the ES cluster.
`openshift_logging_es_memory_limit`	Amount of RAM to reserve per Elasticsearch instance. It must be at least 512M. Possible suffixes are G,g,M,m.
`openshift_logging_es_number_of_replicas`	The number of replica shards per primary shard for every new index. Defaults to '0'. A minimum of `1` is advisable for production clusters.
`openshift_logging_es_number_of_shards`	The number of primary shards for every new index created in ES. Defaults to '1'.
`openshift_logging_es_pv_selector`	A key/value map added to a PVC in order to select specific PVs.
`openshift_logging_es_pvc_dynamic`	Set to `true` to have PVC claims annotated so that their backing storage is dynamically provisioned. When set to `true` the storage class is ignored and not set to the PVC.
`openshift_logging_es_pvc_storage_class_name`	To use a non-default storage class, set the variable with the storage class name. For example, set to one of the following, `openshift_logging_es_pvc_storage_class_name=glusterprovisioner` or `openshift_logging_es_pvc_storage_class_name=cephrbdprovisioner`.
`openshift_logging_es_pvc_size`	Size of the persistent volume claim to create per Elasticsearch instance. For example, 100G. If omitted, no PVCs are created and ephemeral volumes are used instead.
`openshift_logging_es_pvc_prefix`	Prefix for the names of persistent volume claims to be used as storage for Elasticsearch instances. A number is appended per instance, such as logging-es-1. If they do not already exist, they are created with size `es-pvc-size`. When `openshift_logging_es_pvc_prefix` is set, and: `openshift_logging_es_pvc_dynamic`=`true`, the value for `openshift_logging_es_pvc_size` is optional. `openshift_logging_es_pvc_dynamic`=`false`, the value for `openshift_logging_es_pvc_size` must be set.
`openshift_logging_es_recover_after_time`	The amount of time ES will wait before it tries to recover.
`openshift_logging_es_storage_group`	Number of a supplemental group ID for access to Elasticsearch storage volumes. Backing volumes should allow access by this group ID.
`openshift_logging_es_nodeselector`	A node selector specified as a map that determines which nodes are eligible targets for deploying Elasticsearch instances. This can be used to place these instances on nodes reserved or optimized for running them. For example, the selector could be `{"node-type":"infrastructure"}`. At least one active node must have this label before Elasticsearch will deploy.
`openshift_logging_es_ops_host`	Equivalent to `openshift_logging_es_host` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_port`	Equivalent to `openshift_logging_es_port` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_ca`	Equivalent to `openshift_logging_es_ca` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_client_cert`	Equivalent to `openshift_logging_es_client_cert` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_client_key`	Equivalent to `openshift_logging_es_client_key` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_cluster_size`	Equivalent to `openshift_logging_es_cluster_size` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_cpu_limit`	Equivalent to `openshift_logging_es_cpu_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_memory_limit`	Equivalent to `openshift_logging_es_memory_limit` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_pv_selector`	Equivalent to `openshift_logging_es_pv_selector` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_pvc_dynamic`	Equivalent to `openshift_logging_es_pvc_dynamic` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_pvc_size`	Equivalent to `openshift_logging_es_pvc_size` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_pvc_prefix`	Equivalent to `openshift_logging_es_pvc_prefix` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_recover_after_time`	Equivalent to `openshift_logging_es_recovery_after_time` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_storage_group`	Equivalent to `openshift_logging_es_storage_group` for Ops cluster when `openshift_logging_use_ops` is set to `true`.
`openshift_logging_es_ops_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Elasticsearch instances. This can be used to place these instances on nodes reserved or optimized for running them. For example, the selector could be `node-type=infrastructure`. At least one active node must have this label before Elasticsearch will deploy.
`openshift_logging_elasticsearch_kibana_index_mode`	The default value, `unique`, allows users to each have their own Kibana index. In this mode, their saved queries, visualizations, and dashboards are not shared. You may also set the value `shared_ops`. In this mode, all operations users share a Kibana index which allows each operations user to see the the same queries, visualizations, and dashboards.
`openshift_logging_kibana_ops_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Kibana instances.
`openshift_logging_curator_ops_nodeselector`	A node selector that specifies which nodes are eligible targets for deploying Curator instances.

Custom Certificates

You can specify custom certificates using the following inventory variables instead of relying on those generated during the deployment process. These certificates are used to encrypt and secure communication between a user’s browser and Kibana. The security-related files will be generated if they are not supplied.

File Name	Description
`openshift_logging_kibana_cert`	A browser-facing certificate for the Kibana server.
`openshift_logging_kibana_key`	A key to be used with the browser-facing Kibana certificate.
`openshift_logging_kibana_ca`	The absolute path on the control node to the CA file to use for the browser facing Kibana certs.
`openshift_logging_kibana_ops_cert`	A browser-facing certificate for the Ops Kibana server.
`openshift_logging_kibana_ops_key`	A key to be used with the browser-facing Ops Kibana certificate.
`openshift_logging_kibana_ops_ca`	The absolute path on the control node to the CA file to use for the browser facing ops Kibana certs.

30.4. Deploying the EFK Stack

The EFK stack is deployed using an Ansible playbook to the EFK components. Run the playbook from the default OpenShift Ansible location using the default inventory file.

$ ansible-playbook [-i </path/to/inventory>] \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/openshift-logging.yml

Running the playbook deploys all resources needed to support the stack; such as Secrets, ServiceAccounts, and DeploymentConfigs. The playbook waits to deploy the component pods until the stack is running. If the wait steps fail, the deployment could still be successful; it may be retrieving the component images from the registry which can take up to a few minutes. You can watch the process with:

$ oc get pods -w

They will eventually enter Running status. For additional details about the status of the pods during deployment by retrieving associated events:

$ oc describe pods/<pod_name>

Check the logs if the pods do not run successfully:

$ oc logs -f <pod_name>

30.5. Understanding and Adjusting the Deployment

This section describes adjustments that you can make to deployed components.

30.5.1. Ops Cluster

Note

The logs for the default, openshift, and openshift-infra projects are automatically aggregated and grouped into the .operations item in the Kibana interface.

The project where you have deployed the EFK stack (logging, as documented here) is not aggregated into .operations and is found under its ID.

If you set openshift_logging_use_ops to true in your inventory file, Fluentd is configured to split logs between the main Elasticsearch cluster and another cluster reserved for operations logs, which are defined as node system logs and the projects default, openshift, and openshift-infra. Therefore, a separate Elasticsearch cluster, a separate Kibana, and a separate Curator are deployed to index, access, and manage operations logs. These deployments are set apart with names that include -ops. Keep these separate deployments in mind if you enable this option. Most of the following discussion also applies to the operations cluster if present, just with the names changed to include -ops.

30.5.2. Elasticsearch

A highly-available environment requires at least three replicas of Elasticsearch; each on a different host. Elasticsearch replicas require their own storage, but an OpenShift Container Platform deployment configuration shares storage volumes between all its pods. So, when scaled up, the EFK deployer ensures each replica of Elasticsearch has its own deployment configuration.

It is possible to scale your cluster up after creation by modifying the openshift_logging_es_cluser_size in the inventory file and re-running the logging playbook. Additional clustering parameters can be modified and are described in Specifying Logging Ansible Variables.

Refer to Elastic’s documentation for considerations involved in choosing storage and network location as directed below.

Viewing all Elasticsearch Deployments

To view all current Elasticsearch deployments:

$ oc get dc --selector logging-infra=elasticsearch

Node Selector

Because Elasticsearch can use a lot of resources, all members of a cluster should have low latency network connections to each other and to any remote storage. Ensure this by directing the instances to dedicated nodes, or a dedicated region within your cluster, using a node selector.

To configure a node selector, specify the openshift_logging_es_nodeselector configuration option in the inventory file. This applies to all Elasticsearch deployments; if you need to individualize the node selectors, you must manually edit each deployment configuration after deployment. The node selector is specified as a python compatible dict. For example, {"node-type":"infra", "region":"east"}.

Persistent Elasticsearch Storage

By default, the openshift_logging Ansible role creates an ephemeral deployment in which all of a pod’s data is lost upon restart. For production usage, specify a persistent storage volume for each Elasticsearch deployment configuration. You can create the necessary persistent volume claims before deploying or have them created for you. The PVCs must be named to match the openshift_logging_es_pvc_prefix setting, which defaults to logging-es; each PVC name will have a sequence number added to it: logging-es-0, logging-es-1, logging-es-2, and so on. If a PVC needed for the deployment exists already, it is used; if not, and openshift_logging_es_pvc_size has been specified, it is created with a request for that size.

Warning

Using NFS storage as a volume or a persistent volume (or via NAS such as Gluster) is not supported for Elasticsearch storage, as Lucene relies on file system behavior that NFS does not supply. Data corruption and other problems can occur. If NFS storage is a requirement, you can allocate a large file on a volume to serve as a storage device and mount it locally on one host. For example, if your NFS storage volume is mounted at /nfs/storage:

$ truncate -s 1T /nfs/storage/elasticsearch-1
$ mkfs.xfs /nfs/storage/elasticsearch-1
$ mount -o loop /nfs/storage/elasticsearch-1 /usr/local/es-storage
$ chown 1000:1000 /usr/local/es-storage

Then, use /usr/local/es-storage as a host-mount as described below. Use a different backing file as storage for each Elasticsearch replica.

This loopback must be maintained manually outside of OpenShift Container Platform, on the node. You must not maintain it from inside a container.

It is possible to use a local disk volume (if available) on each node host as storage for an Elasticsearch replica. Doing so requires some preparation as follows.

The relevant service account must be given the privilege to mount and edit a local volume:
```
$ oc adm policy add-scc-to-user privileged  \
       system:serviceaccount:logging:aggregated-logging-elasticsearch 1
```
1
Use the project you created earlier (for example, logging) when running the logging playbook.

Each Elasticsearch replica definition must be patched to claim that privilege, for example (change to --selector component=es-ops for Ops cluster):

$ for dc in $(oc get deploymentconfig --selector component=es -o name); do
    oc scale $dc --replicas=0
    oc patch $dc \
       -p '{"spec":{"template":{"spec":{"containers":[{"name":"elasticsearch","securityContext":{"privileged": true}}]}}}}'
  done

The Elasticsearch replicas must be located on the correct nodes to use the local storage, and should not move around even if those nodes are taken down for a period of time. This requires giving each Elasticsearch replica a node selector that is unique to a node where an administrator has allocated storage for it. To configure a node selector, edit each Elasticsearch deployment configuration and add or edit the nodeSelector section to specify a unique label that you have applied for each desired node:
```
apiVersion: v1
kind: DeploymentConfig
spec:
  template:
    spec:
      nodeSelector:
        logging-es-node: "1" 1
```
1
This label should uniquely identify a replica with a single node that bears that label, in this case logging-es-node=1. Use the oc label command to apply labels to nodes as needed.
To automate applying the node selector you can instead use the oc patch command:
```
$ oc patch dc/logging-es-<suffix> \
   -p '{"spec":{"template":{"spec":{"nodeSelector":{"logging-es-node":"1"}}}}}'
```

Once these steps are taken, a local host mount can be applied to each replica as in this example (where we assume storage is mounted at the same path on each node) (change to --selector component=es-ops for Ops cluster):

$ for dc in $(oc get deploymentconfig --selector component=es -o name); do
    oc set volume $dc \
          --add --overwrite --name=elasticsearch-storage \
          --type=hostPath --path=/usr/local/es-storage
    oc rollout latest $dc
    oc scale $dc --replicas=1
  done

Changing the Scale of Elasticsearch

If you need to scale up the number of Elasticsearch instances your cluster uses, it is not as simple as scaling up an Elasticsearch deployment configuration. This is due to the nature of persistent volumes and how Elasticsearch is configured to store its data and recover the cluster. Instead, scaling up requires creating a deployment configuration for each Elasticsearch cluster node.

The simplest way to change the scale of Elasticsearch is to modify the inventory host file and re-run the logging playbook as described previously. Assuming you have supplied persistent storage for the deployment, this should not be disruptive.

Note

Resizing an Elasticsearch cluster using the logging playbook is only possible when the new openshift_logging_es_cluster_size value is higher than the current number of Elasticsearch nodes (scaled up) in the cluster.

If you do not wish to reinstall, for instance because you have made customizations that you would like to preserve, then it is possible to add new Elasticsearch deployment configurations to the cluster using a template supplied by the deployer. This requires a more complicated procedure however.

Expose Elasticsearch as a Route

By default, Elasticsearch deployed with OpenShift aggregated logging is not accessible from outside the logging cluster. You can enable a route for external access to Elasticsearch for those tools that want to access its data.

You have access to Elasticsearch using your OpenShift token, and you can provide the external Elasticsearch and Elasticsearch Ops hostnames when creating the server certificate (similar to Kibana).

To access Elasticsearch as a reencrypt route, define the following variables:

openshift_logging_es_allow_external=True
openshift_logging_es_hostname=elasticsearch.example.com

Run the openshift-logging.yml Ansible playbook:

$ ansible-playbook [-i </path/to/inventory>] \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/openshift-logging.yml

To log in to Elasticsearch remotely, the request must contain three HTTP headers:

Authorization: Bearer $token
X-Proxy-Remote-User: $username
X-Forwarded-For: $ip_address

You must have access to the project in order to be able to access to the logs. For example:
```
$ oc login <user1>
$ oc new-project <user1project>
$ oc new-app <httpd-example>
```
You need to get the token of this ServiceAccount to be used in the request:
```
$ token=$(oc whoami -t)
```

Using the token previously configured, you should be able access Elasticsearch through the exposed route:

$ curl -k -H "Authorization: Bearer $token" -H "X-Proxy-Remote-User: $(oc whoami)" -H "X-Forwarded-For: 127.0.0.1" https://es.example.test/_cat/indices

30.5.3. Fluentd

Fluentd is deployed as a DaemonSet that deploys replicas according to a node label selector, which you can specify with the inventory parameter openshift_logging_fluentd_nodeselector and the default is logging-infra-fluentd. As part of the OpenShift cluster installation, it is recommended that you add the Fluentd node selector to the list of persisted node labels.

Fluentd uses journald as the system log source. These are log messages from the operating system, Docker, and OpenShift. For container logs, Fluentd determines which log driver Docker is using, json-file or journald, and automatically reads the logs from that source.

Note

As of OpenShift Container Platform 3.3, Fluentd no longer reads historical log files when using the JSON file log driver. In situations where clusters have a large number of log files and are older than the EFK deployment, this avoids delays when pushing the most recent logs into Elasticsearch. Curator deleting logs are migrated soon after they are added to Elasticsearch.

Note

It may require several minutes, or hours, depending on the size of your journal, before any new log entries are available in Elasticsearch, when using openshift_logging_journal_read_from_head=true.

Warning

It is highly recommended that you use the default value for use-journal. In scenarios where upgrading OpenShift Container Platform changes the Docker log driver, if use-journal=False is explicitly specified as part of installation, Fluentd still expects to read logs generated using the json-file log driver. This results in a lack of log ingestion. If this has happened within your logging cluster, troubleshoot it.

See Updating Fluentd’s Log Source After a Docker Log Driver Update for more information.

Configuring Fluentd to Send Logs to an External Log Aggregator

You can configure Fluentd to send a copy of its logs to an external log aggregator, and not the default Elasticsearch, using the secure-forward plug-in. From there, you can further process log records after the locally hosted Fluentd has processed them.

The logging deployment provides a secure-forward.conf section in the Fluentd configmap for configuring the external aggregator:

<store>
@type secure_forward
self_hostname pod-${HOSTNAME}
shared_key thisisasharedkey
secure yes
enable_strict_verification yes
ca_cert_path /etc/fluent/keys/your_ca_cert
ca_private_key_path /etc/fluent/keys/your_private_key
ca_private_key_passphrase passphrase
<server>
  host ose1.example.com
  port 24284
</server>
<server>
  host ose2.example.com
  port 24284
  standby
</server>
<server>
  host ose3.example.com
  port 24284
  standby
</server>
</store>

This can be updated using the oc edit command:

$ oc edit configmap/logging-fluentd

Certificates to be used in secure-forward.conf can be added to the existing secret that is mounted on the Fluentd pods. The your_ca_cert and your_private_key values must match what is specified in secure-forward.conf in configmap/logging-fluentd:

$ oc patch secrets/logging-fluentd --type=json \
  --patch "[{'op':'add','path':'/data/your_ca_cert','value':'$(base64 /path/to/your_ca_cert.pem)'}]"
$ oc patch secrets/logging-fluentd --type=json \
  --patch "[{'op':'add','path':'/data/your_private_key','value':'$(base64 /path/to/your_private_key.pem)'}]"

Note

Replace your_private_key with a generic name. This is a link to the JSON path, not a path on your host system

When configuring the external aggregator, it must be able to accept messages securely from Fluentd.

If the external aggregator is another Fluentd server, it must have the fluent-plugin-secure-forward plug-in installed and make use of the input plug-in it provides:

<source>
  @type secure_forward

  self_hostname ${HOSTNAME}
  bind 0.0.0.0
  port 24284

  shared_key thisisasharedkey

  secure yes
  cert_path        /path/for/certificate/cert.pem
  private_key_path /path/for/certificate/key.pem
  private_key_passphrase secret_foo_bar_baz
</source>

Further explanation of how to set up the fluent-plugin-secure-forward plug-in can be found here.

Reducing the Number of Connections from Fluentd to the API Server

With mux, you can deploy N number of mux services, where N is fewer than the number of nodes. Each Fluentd is configured with USE_MUX_CLIENT=1. This tells Fluentd to send the raw logs to mux with no filtering and no Kubernetes metadata filtering, which involves connections to the API server. You can perform all of the processing and Kubernetes metadata filtering with mux.

Important

The mux is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs), might not be functionally complete, and Red Hat does not recommend to use them for production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information on Red Hat Technology Preview features support scope, see https://access.redhat.com/support/offerings/techpreview/.

Parameter	Description
`openshift_logging_use_mux`	The default is set to `False`. If set to `True`, a service called `mux` is deployed. This service acts as a Fluentd `secure_forward` aggregator for the node agent Fluentd daemonsets running in the cluster. Use `openshift_logging_use_mux` to reduce the number of connections to the OpenShift API server, and configure each node in Fluentd to send raw logs to `mux` and turn off the Kubernetes metadata plug-in.
`openshift_logging_mux_allow_external`	The default is set to `False`. If set to `True`, the `mux` service is deployed, and it is configured to allow Fluentd clients running outside of the cluster to send logs using `secure_forward`. This allows OpenShift logging to be used as a central logging service for clients other than OpenShift, or other OpenShift clusters.
`openshift_logging_use_mux_client`	The default is set to `False`. If set to `True`, the node agent Fluentd services is configured to send logs to the `mux` service rather than directly to Elasticsearch, and their Kubernetes metadata filters is disabled, reducing the number of connections to the API server.
`openshift_logging_mux_hostname`	The default is `mux` plus `openshift_master_default_subdomain`. This is the hostname `external_clients` will use to connect to `mux`, and is used in the TLS server cert subject.
`openshift_logging_mux_port`	24284
`openshift_logging_mux_cpu_limit`	500M
`openshift_logging_mux_memory_limit`	1Gi
`openshift_logging_mux_default_namespaces`	The default is `mux-undefined`. The first value in the list is the namespace to use for undefined projects, followed by any additional namespaces to create by default. Usually, you do not need to set this value.
`openshift_logging_mux_namespaces`	The default value is empty, allowing for additional namespaces to create for external `mux` clients to associate with their logs. You will need to set this value.

Throttling logs in Fluentd

For projects that are especially verbose, an administrator can throttle down the rate at which the logs are read in by Fluentd before being processed.

Warning

Throttling can contribute to log aggregation falling behind for the configured projects; log entries can be lost if a pod is deleted before Fluentd catches up.

Note

Throttling does not work when using the systemd journal as the log source. The throttling implementation depends on being able to throttle the reading of the individual log files for each project. When reading from the journal, there is only a single log source, no log files, so no file-based throttling is available. There is not a method of restricting the log entries that are read into the Fluentd process.

To tell Fluentd which projects it should be restricting, edit the throttle configuration in its ConfigMap after deployment:

$ oc edit configmap/logging-fluentd

The format of the throttle-config.yaml key is a YAML file that contains project names and the desired rate at which logs are read in on each node. The default is 1000 lines at a time per node. For example:

logging:
  read_lines_limit: 500

test-project:
  read_lines_limit: 10

.operations:
  read_lines_limit: 100

When you make changes to any part of the EFK stack, specifically Elasticsearch or Fluentd, you should first scale Elasicsearch down to zero and scale Fluentd so it does not match any other nodes. Then, make the changes and scale Elasicsearch and Fluentd back.

To scale Elasicsearch to zero:

$ oc scale --replicas=0 dc/<ELASTICSEARCH_DC>

Change nodeSelector in the daemonset configuration to match zero:

Get the fluentd node selector:

$ oc get ds logging-fluentd -o yaml |grep -A 1 Selector
     nodeSelector:
       logging-infra-fluentd: "true"

Use the oc patch command to modify the daemonset nodeSelector:

$ oc patch ds logging-fluentd -p '{"spec":{"template":{"spec":{"nodeSelector":{"nonexistlabel":"true"}}}}}'

Get the fluentd node selector:

$ oc get ds logging-fluentd -o yaml |grep -A 1 Selector
     nodeSelector:
       "nonexistlabel: "true"

Scale Elastcsearch back up from zero:

$ oc scale --replicas=# dc/<ELASTICSEARCH_DC>

Change nodeSelector in the daemonset configuration back to logging-infra-fluentd: "true".

Use the oc patch command to modify the daemonset nodeSelector:

oc patch ds logging-fluentd -p '{"spec":{"template":{"spec":{"nodeSelector":{"logging-infra-fluentd":"true"}}}}}'

30.5.4. Kibana

To access the Kibana console from the OpenShift Container Platform web console, add the loggingPublicURL parameter in the /etc/origin/master/master-config.yaml file, with the URL of the Kibana console (the kibana-hostname parameter). The value must be an HTTPS URL:

...
assetConfig:
  ...
  loggingPublicURL: "https://kibana.example.com"
...

Setting the loggingPublicURL parameter creates a View Archive button on the OpenShift Container Platform web console under the Browse → Pods → <pod_name> → Logs tab. This links to the Kibana console.

You can scale the Kibana deployment as usual for redundancy:

$ oc scale dc/logging-kibana --replicas=2

Note

To ensure the scale persists across multiple executions of the logging playbook, make sure to update the openshift_logging_kibana_replica_count in the inventory file.

You can see the user interface by visiting the site specified by the openshift_logging_kibana_hostname variable.

See the Kibana documentation for more information on Kibana.

Kibana Visualize

Kibana Visualize enables you to create visualizations and dashboards for monitoring container and pod logs allows administrator users (cluster-admin or cluster-reader) to view logs by deployment, namespace, pod, and container.

Kibana Visualize exists inside the Elasticsearch and ES-OPS pod, and must be run inside those pods. To load dashboards and other Kibana UI objects, you must first log into Kibana as the user you want to add the dashboards to, then log out. This will create the necessary per-user configuration that the next step relies on. Then, run:

$ oc exec <$espod> -- es_load_kibana_ui_objects <user-name>

Where $espod is the name of any one of your Elasticsearch pods.

30.5.5. Curator

Curator allows administrators to configure scheduled Elasticsearch maintenance operations to be performed automatically on a per-project basis. It is scheduled to perform actions daily based on its configuration. Only one Curator pod is recommended per Elasticsearch cluster. Curator is configured via a YAML configuration file with the following structure:

$PROJECT_NAME:
  $ACTION:
    $UNIT: $VALUE

$PROJECT_NAME:
  $ACTION:
    $UNIT: $VALUE
 ...

The available parameters are:

Variable Name	Description
`$PROJECT_NAME`	The actual name of a project, such as myapp-devel. For OpenShift Container Platform operations logs, use the name `.operations` as the project name.
`$ACTION`	The action to take, currently only `delete` is allowed.
`$UNIT`	One of `days`, `weeks`, or `months`.
`$VALUE`	An integer for the number of units.
`.defaults`	Use `.defaults` as the `$PROJECT_NAME` to set the defaults for projects that are not specified.
`runhour`	(Number) the hour of the day in 24-hour format at which to run the Curator jobs. For use with `.defaults`.
`runminute`	(Number) the minute of the hour at which to run the Curator jobs. For use with `.defaults`.

For example, to configure Curator to:

delete indices in the myapp-dev project older than 1 day
delete indices in the myapp-qe project older than 1 week
delete operations logs older than 8 weeks
delete all other projects indices after they are 30 days old
run the Curator jobs at midnight every day

Use:

myapp-dev:
 delete:
   days: 1

myapp-qe:
  delete:
    weeks: 1

.operations:
  delete:
    weeks: 8

.defaults:
  delete:
    days: 30
  runhour: 0
  runminute: 0

Important

When you use month as the $UNIT for an operation, Curator starts counting at the first day of the current month, not the current day of the current month. For example, if today is April 15, and you want to delete indices that are 2 months older than today (delete: months: 2), Curator does not delete indices that are dated older than February 15; it deletes indices older than February 1. That is, it goes back to the first day of the current month, then goes back two whole months from that date. If you want to be exact with Curator, it is best to use days (for example, delete: days: 30).

30.5.5.1. Creating the Curator Configuration

The openshift_logging Ansible role provides a ConfigMap from which Curator reads its configuration. You may edit or replace this ConfigMap to reconfigure Curator. Currently the logging-curator ConfigMap is used to configure both your ops and non-ops Curator instances. Any .operations configurations are in the same location as your application logs configurations.

To edit the provided ConfigMap to configure your Curator instances:
```
$ oc edit configmap/logging-curator
```

To replace the provided ConfigMap instead:

$ create /path/to/mycuratorconfig.yaml
$ oc create configmap logging-curator -o yaml \
  --from-file=config.yaml=/path/to/mycuratorconfig.yaml | \
  oc replace -f -

After you make your changes, redeploy Curator:

$ oc rollout latest dc/logging-curator
$ oc rollout latest dc/logging-curator-ops

30.6. Cleanup

Remove everything generated during the deployment.

$ ansible-playbook [-i </path/to/inventory>] \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/openshift-logging.yml \

30.7. Troubleshooting Kibana

Using the Kibana console with OpenShift Container Platform can cause problems that are easily solved, but are not accompanied with useful error messages. Check the following troubleshooting sections if you are experiencing any problems when deploying Kibana on OpenShift Container Platform:

Login Loop

The OAuth2 proxy on the Kibana console must share a secret with the master host’s OAuth2 server. If the secret is not identical on both servers, it can cause a login loop where you are continuously redirected back to the Kibana login page.

To fix this issue, delete the current OAuthClient, and use openshift-ansible to re-run the openshift_logging role:

$ oc delete oauthclient/kibana-proxy
$ ansible-playbook [-i </path/to/inventory>] \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/openshift-logging.yml

Cryptic Error When Viewing the Console

When attempting to visit the Kibana console, you may receive a browser error instead:

{"error":"invalid_request","error_description":"The request is missing a required parameter,
 includes an invalid parameter value, includes a parameter more than once, or is otherwise malformed."}

This can be caused by a mismatch between the OAuth2 client and server. The return address for the client must be in a whitelist so the server can securely redirect back after logging in.

Fix this issue by replacing the OAuthClient entry:

$ oc delete oauthclient/kibana-proxy
$ ansible-playbook [-i </path/to/inventory>] \
    /usr/share/ansible/openshift-ansible/playbooks/byo/openshift-cluster/openshift-logging.yml

If the problem persists, check that you are accessing Kibana at a URL listed in the OAuth client. This issue can be caused by accessing the URL at a forwarded port, such as 1443 instead of the standard 443 HTTPS port. You can adjust the server whitelist by editing the OAuth client:

$ oc edit oauthclient/kibana-proxy

503 Error When Viewing the Console

If you receive a proxy error when viewing the Kibana console, it could be caused by one of two issues.

First, Kibana may not be recognizing pods. If Elasticsearch is slow in starting up, Kibana may timeout trying to reach it. Check whether the relevant service has any endpoints:

$ oc describe service logging-kibana
Name:                   logging-kibana
[...]
Endpoints:              <none>

If any Kibana pods are live, endpoints are listed. If they are not, check the state of the Kibana pods and deployment. You may need to scale the deployment down and back up again.

The second possible issue may be caused if the route for accessing the Kibana service is masked. This can happen if you perform a test deployment in one project, then deploy in a different project without completely removing the first deployment. When multiple routes are sent to the same destination, the default router will only route to the first created. Check the problematic route to see if it is defined in multiple places:

$ oc get route  --all-namespaces --selector logging-infra=support

F-5 Load Balancer and X-Forwarded-For Enabled

If you are attempting to use a F-5 load balancer in front of Kibana with X-Forwarded-For enabled, this can cause an issue in which the Elasticsearch Searchguard plug-in is unable to correctly accept connections from Kibana.

Example Kibana Error Message

Kibana: Unknown error while connecting to Elasticsearch

Error: Unknown error while connecting to Elasticsearch
Error: UnknownHostException[No trusted proxies]

To configure Searchguard to ignore the extra header:

Scale down all Fluentd pods.
Scale down Elasticsearch after the Fluentd pods have terminated.
Add searchguard.http.xforwardedfor.header: DUMMY to the Elasticsearch configuration section.
```
$ oc edit configmap/logging-elasticsearch 1
```
1
This approach requires that Elasticsearch’s configurations are within a ConfigMap.
Scale Elasticsearch back up.
Scale up all Fluentd pods.

30.8. Sending Logs to an External Elasticsearch Instance

Fluentd sends logs to the value of the ES_HOST, ES_PORT, OPS_HOST, and OPS_PORT environment variables of the Elasticsearch deployment configuration. The application logs are directed to the ES_HOST destination, and operations logs to OPS_HOST.

Note

Sending logs directly to an AWS Elasticsearch instance is not supported. Use Fluentd Secure Forward to direct logs to an instance of Fluentd that you control and that is configured with the fluent-plugin-aws-elasticsearch-service plug-in.

To direct logs to a specific Elasticsearch instance, edit the deployment configuration and replace the value of the above variables with the desired instance:

$ oc edit dc/<deployment_configuration>

For an external Elasticsearch instance to contain both application and operations logs, you can set ES_HOST and OPS_HOST to the same destination, while ensuring that ES_PORT and OPS_PORT also have the same value.

If your externally hosted Elasticsearch instance does not use TLS, update the _CLIENT_CERT, _CLIENT_KEY, and _CA variables to be empty. If it does use TLS, but not mutual TLS, update the _CLIENT_CERT and _CLIENT_KEY variables to be empty and patch or recreate the logging-fluentd secret with the appropriate _CA value for communicating with your Elasticsearch instance. If it uses Mutual TLS as the provided Elasticsearch instance does, patch or recreate the logging-fluentd secret with your client key, client cert, and CA.

Note

If you are not using the provided Kibana and Elasticsearch images, you will not have the same multi-tenant capabilities and your data will not be restricted by user access to a particular project.

30.9. Sending Logs to an External Syslog Server

Use the fluent-plugin-remote-syslog plug-in on the host to send logs to an external syslog server.

Set environment variables in the logging-fluentd or logging-mux deployment configurations:

- name: REMOTE_SYSLOG_HOST 1
  value: host1
- name: REMOTE_SYSLOG_HOST_BACKUP
  value: host2
- name: REMOTE_SYSLOG_PORT_BACKUP
  value: 5555

1: The desired remote syslog host. Required for each host.

This will build two destinations. The syslog server on host1 will be receiving messages on the default port of 514, while host2 will be receiving the same messages on port 5555.

Alternatively, you can configure your own custom fluent.conf in the logging-fluentd or logging-mux ConfigMaps.

Fluentd Environment Variables

Parameter	Description
`USE_REMOTE_SYSLOG`	Defaults to `false`. Set to `true` to enable use of the `fluent-plugin-remote-syslog` gem
`REMOTE_SYSLOG_HOST`	(Required) Hostname or IP address of the remote syslog server.
`REMOTE_SYSLOG_PORT`	Port number to connect on. Defaults to `514`.
`REMOTE_SYSLOG_SEVERITY`	Set the syslog severity level. Defaults to `debug`.
`REMOTE_SYSLOG_FACILITY`	Set the syslog facility. Defaults to `local0`.
`REMOTE_SYSLOG_USE_RECORD`	Defaults to `false`. Set to `true` to use the record’s severity and facility fields to set on the syslog message.
`REMOTE_SYSLOG_REMOVE_TAG_PREFIX`	Removes the prefix from the tag, defaults to `''` (empty).
`REMOTE_SYSLOG_TAG_KEY`	If specified, uses this field as the key to look on the record, to set the tag on the syslog message.
`REMOTE_SYSLOG_PAYLOAD_KEY`	If specified, uses this field as the key to look on the record, to set the payload on the syslog message.

Warning

This implementation is insecure, and should only be used in environments where you can guarantee no snooping on the connection.

Fluentd Logging Ansible Variables

Parameter	Description
`openshift_logging_fluentd_remote_syslog`	The default is set to `false`. Set to `true` to enable use of the fluent-plugin-remote-syslog gem.
`openshift_logging_fluentd_remote_syslog_host`	Hostname or IP address of the remote syslog server, this is mandatory.
`openshift_logging_fluentd_remote_syslog_port`	Port number to connect on, defaults to `514`.
`openshift_logging_fluentd_remote_syslog_severity`	Set the syslog severity level, defaults to `debug`.
`openshift_logging_fluentd_remote_syslog_facility`	Set the syslog facility, defaults to `local0`.
`openshift_logging_fluentd_remote_syslog_use_record`	The default is set to `false`. Set to `true` to use the record’s severity and facility fields to set on the syslog message.
`openshift_logging_fluentd_remote_syslog_remove_tag_prefix`	Removes the prefix from the tag, defaults to `''` (empty).
`openshift_logging_fluentd_remote_syslog_tag_key`	If string is specified, uses this field as the key to look on the record, to set the tag on the syslog message.
`openshift_logging_fluentd_remote_syslog_payload_key`	If string is specified, uses this field as the key to look on the record, to set the payload on the syslog message.

Mux Logging Ansible Variables

Parameter	Description
`openshift_logging_mux_remote_syslog`	The default is set to `false`. Set to `true` to enable use of the fluent-plugin-remote-syslog gem.
`openshift_logging_mux_remote_syslog_host`	Hostname or IP address of the remote syslog server, this is mandatory.
`openshift_logging_mux_remote_syslog_port`	Port number to connect on, defaults to `514`.
`openshift_logging_mux_remote_syslog_severity`	Set the syslog severity level, defaults to `debug`.
`openshift_logging_mux_remote_syslog_facility`	Set the syslog facility, defaults to `local0`.
`openshift_logging_mux_remote_syslog_use_record`	The default is set to `false`. Set to `true` to use the record’s severity and facility fields to set on the syslog message.
`openshift_logging_mux_remote_syslog_remove_tag_prefix`	Removes the prefix from the tag, defaults to `''` (empty).
`openshift_logging_mux_remote_syslog_tag_key`	If string is specified, uses this field as the key to look on the record, to set the tag on the syslog message.
`openshift_logging_mux_remote_syslog_payload_key`	If string is specified, uses this field as the key to look on the record, to set the payload on the syslog message.

30.10. Performing Administrative Elasticsearch Operations

As of logging version 3.2.0, an administrator certificate, key, and CA that can be used to communicate with and perform administrative operations on Elasticsearch are provided within the logging-elasticsearch secret.

Note

To confirm whether or not your EFK installation provides these, run:

$ oc describe secret logging-elasticsearch

If they are not available, refer to Manual Upgrades to ensure you are on the latest version first.

Connect to an Elasticsearch pod that is in the cluster on which you are attempting to perform maintenance.

To find a pod in a cluster use either:

$ oc get pods -l component=es -o name | head -1
$ oc get pods -l component=es-ops -o name | head -1

Connect to a pod:
```
$ oc rsh <your_Elasticsearch_pod>
```
Once connected to an Elasticsearch container, you can use the certificates mounted from the secret to communicate with Elasticsearch per its Indices APIs documentation.
Fluentd sends its logs to Elasticsearch using the index format project.{project_name}.{project_uuid}.YYYY.MM.DD where YYYY.MM.DD is the date of the log record.
For example, to delete all logs for the logging project with uuid 3b3594fa-2ccd-11e6-acb7-0eb6b35eaee3 from June 15, 2016, we can run:
```
$ curl --key /etc/elasticsearch/secret/admin-key \
  --cert /etc/elasticsearch/secret/admin-cert \
  --cacert /etc/elasticsearch/secret/admin-ca -XDELETE \
  "https://localhost:9200/project.logging.3b3594fa-2ccd-11e6-acb7-0eb6b35eaee3.2016.06.15"
```

30.11. Changing the Aggregated Logging Driver

By default, aggregated logging uses the journald log driver unless json-file was specified during installation. You can change the log driver between journald and json-file as needed.

Important

When using the json-file driver, ensure that your Docker version is Docker version docker-1.12.6-55.gitc4618fb.el7_4 now or later.

Fluentd determines the driver Docker is using by checking the /etc/docker/daemon.json and /etc/sysconfig/docker files.

You can determine which driver Docker is using with the docker info command:

# docker info | grep Logging

Logging Driver: journald

To change between json-file and journald after installation:

Modify either the /etc/sysconfig/docker or /etc/docker/daemon.json files.

For example:

# cat /etc/sysconfig/docker
OPTIONS=' --selinux-enabled --log-driver=json-file --log-opt max-size=1M --log-opt max-file=3 --signature-verification=False'

cat /etc/docker/daemon.json
{
"log-driver": "json-file",
"log-opts": {
"max-size": "1M",
"max-file": "1"
}
}

Restart the Docker service:
```
systemctl restart docker
```
Update the Fluentd log source.

30.12. Updating Fluentd’s Log Source After a Docker Log Driver Update

If the Docker log driver has changed from json-file to journald and Fluentd was previously configured with USE_JOURNAL=False, then it will not be able to pick up any new logs that are created. When the Fluentd daemonset is configured with the default value for USE_JOURNAL, then it will detect the Docker log driver upon pod start-up, and configure itself to pull from the appropriate source.

To update Fluentd to detect the correct source upon start-up:

Remove the label from nodes where Fluentd is deployed:
```
$ oc label node --all logging-infra-fluentd- 1
```
1
This example assumes use of the default Fluentd node selector and it being deployed on all nodes.

Update the daemonset/logging-fluentd USE_JOURNAL value to be empty:

$ oc patch daemonset/logging-fluentd \
     -p '{"spec":{"template":{"spec":{"containers":[{"name":"fluentd-elasticsearch","env":[{"name": "USE_JOURNAL", "value":""}]}]}}}}'

Relabel your nodes to schedule Fluentd deployments:
```
$ oc label node --all logging-infra-fluentd=true 1
```
1
This example assumes use of the default Fluentd node selector and it being deployed on all nodes.

30.13. Manual Elasticsearch Rollouts

As of OpenShift Container Platform 3.7 the Aggregated Logging stack updated the Elasticsearch Deployment Config object so that it no longer has a Config Change Trigger, meaning any changes to the dc will not result in an automatic rollout. This was to prevent unintended restarts happening in the ES cluster, which could create excessive shard rebalancing as cluster members restart.

This section presents two restart procedures: rolling-restart and full-restart. Where a rolling restart applies appropriate changes to the Elasticsearch cluster without down time (provided three masters are configured) and a full restart safely applies major changes without risk to existing data.

30.13.1. Performing an Elasticsearch Rolling Cluster Restart

A rolling restart is recommended, when any of the following changes are made:

nodes on which Elasticsearch pods run require a reboot
logging-elasticsearch configmap
logging-es-* deployment configuration
new image deployment, or upgrade

This will be the recommended restart policy going forward.

Note

Any action you do for an ES cluster will need to be repeated for the ops cluster if openshift_logging_use_ops was configured to be True.

Prevent shard balancing when purposely bringing down nodes:

$ oc exec -c elasticsearch <any_es_pod_in_the_cluster> --
          curl -s
          --cacert /etc/elasticsearch/secret/admin-ca \
          --cert /etc/elasticsearch/secret/admin-cert \
          --key /etc/elasticsearch/secret/admin-key \
          -XPUT 'https://localhost:9200/_cluster/settings' \
          -d '{ "transient": { "cluster.routing.allocation.enable" : "none" } }'

Once complete, for each dc you have for an ES cluster, run oc rollout latest to deploy the latest version of the dc object:
```
$ oc rollout latest <dc_name>
```
You will see a new pod deployed. Once the pod has two ready containers, you can move on to the next dc.

Once all `dc`s for the cluster have been rolled out, re-enable shard balancing:

$ oc exec -c elasticsearch <any_es_pod_in_the_cluster> --
          curl -s
          --cacert /etc/elasticsearch/secret/admin-ca \
          --cert /etc/elasticsearch/secret/admin-cert \
          --key /etc/elasticsearch/secret/admin-key \
          -XPUT 'https://localhost:9200/_cluster/settings' \
          -d '{ "transient": { "cluster.routing.allocation.enable" : "all" } }'

30.13.2. Performing an Elasticsearch Full Cluster Restart

A full restart is recommended when changing major versions of Elasticsearch or other changes which might put data integrity a risk during the change process.

Note

Any action you do for an ES cluster will need to be repeated for the ops cluster if openshift_logging_use_ops was configured to be True.

Note

When making changes to the logging-es-ops service use components "es-ops-blocked" and "es-ops" instead in the patch

Disable all external communications to the ES cluster while it is down. Edit your non-cluster logging service (for example, logging-es, logging-es-ops) to no longer match the ES pods running:
```
$  oc patch svc/logging-es -p '{"spec":{"selector":{"component":"es-blocked","provider":"openshift"}}}'
```

Prevent shard balancing when purposely bringing down nodes:

$ oc exec -c elasticsearch <any_es_pod_in_the_cluster> --
          curl -s
          --cacert /etc/elasticsearch/secret/admin-ca \
          --cert /etc/elasticsearch/secret/admin-cert \
          --key /etc/elasticsearch/secret/admin-key \
          -XPUT 'https://localhost:9200/_cluster/settings' \
          -d '{ "transient": { "cluster.routing.allocation.enable" : "none" } }'

Perform a shard synced flush to ensure there are no pending operations waiting to be written to disk prior to shutting down:

$ oc exec -c elasticsearch <any_es_pod_in_the_cluster> --
          curl -s
          --cacert /etc/elasticsearch/secret/admin-ca \
          --cert /etc/elasticsearch/secret/admin-cert \
          --key /etc/elasticsearch/secret/admin-key \
          -XPUT 'https://localhost:9200/_flush/synced'

Once complete, for each dc you have for an ES cluster, run oc rollout latest to deploy the latest version of the dc object:
```
$ oc rollout latest <dc_name>
```
You will see a new pod deployed. Once the pod has two ready containers, you can move on to the next dc.

Once all DCs for the cluster have been rolled out, re-enable shard balancing:

$ oc exec -c elasticsearch <any_es_pod_in_the_cluster> --
          curl -s
          --cacert /etc/elasticsearch/secret/admin-ca \
          --cert /etc/elasticsearch/secret/admin-cert \
          --key /etc/elasticsearch/secret/admin-key \
          -XPUT 'https://localhost:9200/_cluster/settings' \
          -d '{ "transient": { "cluster.routing.allocation.enable" : "all" } }'

Once the restart is complete, enable all external communications to the ES cluster. Edit your non-cluster logging service (for example, logging-es, logging-es-ops) to match the ES pods running again:
```
$ oc patch svc/logging-es -p '{"spec":{"selector":{"component":"es","provider":"openshift"}}}'
```

30.1. Overview

30.2. Pre-deployment Configuration

30.3. Specifying Logging Ansible Variables

30.4. Deploying the EFK Stack

30.5. Understanding and Adjusting the Deployment

30.5.1. Ops Cluster

30.5.2. Elasticsearch

30.5.3. Fluentd

30.5.4. Kibana

30.5.5. Curator

30.5.5.1. Creating the Curator Configuration

30.6. Cleanup

30.7. Troubleshooting Kibana

30.8. Sending Logs to an External Elasticsearch Instance

30.9. Sending Logs to an External Syslog Server

30.10. Performing Administrative Elasticsearch Operations

30.11. Changing the Aggregated Logging Driver

30.12. Updating Fluentd’s Log Source After a Docker Log Driver Update

30.13. Manual Elasticsearch Rollouts

30.13.1. Performing an Elasticsearch Rolling Cluster Restart

30.13.2. Performing an Elasticsearch Full Cluster Restart

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