Chapter 5. Master and Node Configuration

5.1. Overview

The openshift start command is used to launch OpenShift servers. The command and its subcommands (master to launch a master server and node to launch a node server) all take a limited set of arguments that are sufficient for launching servers in a development or experimental environment.

However, these arguments are insufficient to describe and control the full set of configuration and security options that are necessary in a production environment. To provide those options, it is necessary to use the dedicated master and node configuration files.

Master configuration files and node configuration files are fully specified with no default values. Therefore, any empty value indicates that you want to start up with an empty value for that parameter. This makes it easy to reason about exactly what your configuration is, but it also makes it difficult to remember all of the options to specify. To make this easier, the configuration files can be created with the --write-config option and then used with the --config option.

5.2. Creating New Configuration Files

For masters, the openshift start command accepts options that indicate that it should simply write the configuration files that it would have used, then terminate. For nodes, a configuration file can be written using the oadm create-node-config command. Creating new configuration files is useful to get a starting point for defining your configuration.

The following commands write the relevant launch configuration file(s), certificate files, and any other necessary files to the specified --write-config or --node-dir directory.

To create configuration files for an all-in-one server (a master and a node on the same host) in the specified directory: 

$ openshift start --write-config=/openshift.local.config

To create a master configuration file and other required files in the specified directory: 

$ openshift start master --write-config=/openshift.local.config/master

To create a node configuration file and other related files in the specified directory: 

$ oadm create-node-config --node-dir=/openshift.local.config/node-<node_hostname> --node=<node_hostname> --hostnames=<hostname>,<ip_address>

For the --hostnames option in the above command, use a comma-delimited list of every host name or IP address you want server certificates to be valid for. The above command also assumes that certificate files are located in an openshift.local.config/master/ directory. If they are not, you can include options to specify their location. Run the command with the -h option to see details.

5.3. Launching Servers Using Configuration Files

Once you have modified the master and/or node configuration files to your specifications, you can use them when launching servers by specifying them as an argument. Keep in mind that if you specify a configuration file, none of the other command line options you pass are respected.

To launch an all-in-one server using a master configuration and a node configuration file: 

$ openshift start --master-config=/openshift.local.config/master/master-config.yaml --node-config=/openshift.local.config/node-<node_hostname>/node-config.yaml

To launch a master server using a master configuration file: 

$ openshift start master --config=/openshift.local.config/master/master-config.yaml

To launch a node server using a node configuration file: 

$ openshift start node --config=/openshift.local.config/node-<node_hostname>/node-config.yaml

5.4. Master Configuration Files

The following master-config.yaml file is a sample master configuration file that was generated with the default values as of writing. You can create a new master configuration file to see the valid options for your installed version of OpenShift.

Example 5.1. Sample Master Configuration File

apiLevels:
- v1beta3
- v1
apiServerArguments:
  event-ttl: 1
  - "15m"
apiVersion: v1
assetConfig:
  logoutURL: ""
  masterPublicURL: https://10.0.2.15:8443
  publicURL: https://10.0.2.15:8443/console/
  servingInfo:
    bindAddress: 0.0.0.0:8443
    certFile: master.server.crt
    clientCA: ""
    keyFile: master.server.key
    maxRequestsInFlight: 0
    requestTimeoutSeconds: 0
controllers: '*'
corsAllowedOrigins:
- 10.0.2.15:8443
- 127.0.0.1
- localhost
disabledFeatures: null
dnsConfig: allowRecursiveQueries: false
  bindAddress: 0.0.0.0:8053
  bindNetwork: tcp4
etcdClientInfo:
  ca: ca.crt
  certFile: master.etcd-client.crt
  keyFile: master.etcd-client.key
  urls:
  - https://10.0.2.15:4001
etcdConfig:
  address: 10.0.2.15:4001
  peerAddress: 10.0.2.15:7001
  peerServingInfo:
    bindAddress: 0.0.0.0:7001
    certFile: etcd.server.crt
    clientCA: ca.crt
    keyFile: etcd.server.key
  servingInfo:
    bindAddress: 0.0.0.0:4001
    certFile: etcd.server.crt
    clientCA: ca.crt
    keyFile: etcd.server.key
  storageDirectory: /root/openshift.local.etcd
etcdStorageConfig:
  kubernetesStoragePrefix: kubernetes.io
  kubernetesStorageVersion: v1
  openShiftStoragePrefix: openshift.io
  openShiftStorageVersion: v1
imageConfig:
  format: openshift/origin-${component}:${version}
  latest: false
kind: MasterConfig
kubeletClientInfo:
  ca: ca.crt
  certFile: master.kubelet-client.crt
  keyFile: master.kubelet-client.key
  port: 10250
kubernetesMasterConfig:
  apiLevels:
  - v1beta3
  - v1
  apiServerArguments: null
  controllerArguments: null
  masterCount: 1
  masterIP: 10.0.2.15
  podEvictionTimeout: 5m
  schedulerConfigFile: ""
  servicesNodePortRange: 30000-32767
  servicesSubnet: 172.30.0.0/16
  staticNodeNames: []
masterClients:
  externalKubernetesKubeConfig: ""
  openshiftLoopbackKubeConfig: openshift-master.kubeconfig
masterPublicURL: https://10.0.2.15:8443
networkConfig:
  clusterNetworkCIDR: 10.1.0.0/16
  hostSubnetLength: 8
  networkPluginName: ""
  serviceNetworkCIDR: 172.30.0.0/16
oauthConfig:
  assetPublicURL: https://10.0.2.15:8443/console/
  grantConfig:
    method: auto
  identityProviders:
  - challenge: true
    login: true
    name: anypassword
    provider:
      apiVersion: v1
      kind: AllowAllPasswordIdentityProvider
  masterPublicURL: https://10.0.2.15:8443
  masterURL: https://10.0.2.15:8443
  sessionConfig:
    sessionMaxAgeSeconds: 300
    sessionName: ssn
    sessionSecretsFile: ""
  tokenConfig:
    accessTokenMaxAgeSeconds: 86400
    authorizeTokenMaxAgeSeconds: 300
policyConfig:
  bootstrapPolicyFile: policy.json
  openshiftInfrastructureNamespace: openshift-infra
  openshiftSharedResourcesNamespace: openshift
projectConfig:
  defaultNodeSelector: ""
  projectRequestMessage: ""
  projectRequestTemplate: ""
  securityAllocator:
    mcsAllocatorRange: s0:/2
    mcsLabelsPerProject: 5
    uidAllocatorRange: 1000000000-1999999999/10000
routingConfig:
  subdomain: router.default.svc.cluster.local
serviceAccountConfig:
  managedNames:
  - default
  - builder
  - deployer
  masterCA: ca.crt
  privateKeyFile: serviceaccounts.private.key
  publicKeyFiles:
  - serviceaccounts.public.key
servingInfo:
  bindAddress: 0.0.0.0:8443
  certFile: master.server.crt
  clientCA: ca.crt
  keyFile: master.server.key
  maxRequestsInFlight: 0
  requestTimeoutSeconds: 3600
1
Prevents memory overload by defining a lower limit (for example, 15m) for stored events. This prevents excessive memory growth that can be the result of etcd storing too many events. By default, this is set to two hours.

5.5. Node Configuration Files

The following node-config.yaml file is a sample node configuration file that was generated with the default values as of writing. You can create a new node configuration file to see the valid options for your installed version of OpenShift.

Example 5.2. Sample Node Configuration File

allowDisabledDocker: true
apiVersion: v1
dnsDomain: cluster.local
dnsIP: 10.0.2.15
dockerConfig:
  execHandlerName: native
imageConfig:
  format: openshift/origin-${component}:${version}
  latest: false
kind: NodeConfig
masterKubeConfig: node.kubeconfig
networkConfig:
  mtu: 1450
  networkPluginName: ""
nodeIP: ""
nodeName: node1.example.com
podManifestConfig: 1
  path: "/path/to/pod-manifest-file" 2
  fileCheckIntervalSeconds: 30 3
servingInfo:
  bindAddress: 0.0.0.0:10250
  certFile: server.crt
  clientCA: node-client-ca.crt
  keyFile: server.key
volumeDirectory: /root/openshift.local.volumes
1
Allows pods to be placed directly on certain set of nodes, or on all nodes without going through the scheduler. You can then use pods to perform the same administrative tasks and support the same services on each node.
2
Specifies the path for the pod manifest file or directory. If it is a directory, then it is expected to contain one or more manifest files. This is used by the Kubelet to create pods on the node.
3
This is the interval (in seconds) for checking the manifest file for new data. The interval must be a positive value.