Chapter 12. Troubleshooting and maintaining the Load-balancing service

Basic troubleshooting and maintenance for the Load-balancing service (octavia) starts with being familiar with the OpenStack client commands for showing status and migrating instances, and knowing how to access logs. If you need to troubleshoot more in depth, you can SSH into one or more Load-balancing service instances (amphorae).

12.1. Verifying the load balancer

You can troubleshoot the Load-balancing service (octavia) and its various components by viewing the output of the load balancer show and list commands.

Procedure

  1. Source your credentials file.

    Example

    $ source ~/overcloudrc

  2. Verify the load balancer (lb1) settings.

    Note

    Values inside parentheses are sample values that are used in the example commands in this procedure. Substitute these sample values with ones that are appropriate for your site.

    Example

    $ openstack loadbalancer show lb1

    Sample output

    +---------------------+--------------------------------------+
| Field               | Value                                |
+---------------------+--------------------------------------+
| admin_state_up      | True                                 |
| created_at          | 2022-02-17T15:59:18                  |
| description         |                                      |
| flavor_id           | None                                 |
| id                  | 265d0b71-c073-40f4-9718-8a182c6d53ca |
| listeners           | 5aaa67da-350d-4125-9022-238e0f7b7f6f |
| name                | lb1                                  |
| operating_status    | ONLINE                               |
| pools               | 48f6664c-b192-4763-846a-da568354da4a |
| project_id          | 52376c9c5c2e434283266ae7cacd3a9c     |
| provider            | amphora                              |
| provisioning_status | ACTIVE                               |
| updated_at          | 2022-02-17T16:01:21                  |
| vip_address         | 192.0.2.177                          |
| vip_network_id      | afeaf55e-7128-4dff-80e2-98f8d1f2f44c |
| vip_port_id         | 94a12275-1505-4cdc-80c9-4432767a980f |
| vip_qos_policy_id   | None                                 |
| vip_subnet_id       | 06ffa90e-2b86-4fe3-9731-c7839b0be6de |
+---------------------+--------------------------------------+

  3. Using the loadbalancer ID (265d0b71-c073-40f4-9718-8a182c6d53ca) from the previous step, obtain the ID of the amphora associated with the load balancer (lb1).

    Example

    $ openstack loadbalancer amphora list | grep 265d0b71-c073-40f4-9718-8a182c6d53ca

    Sample output

    | 1afabefd-ba09-49e1-8c39-41770aa25070 | 265d0b71-c073-40f4-9718-8a182c6d53ca | ALLOCATED | STANDALONE | 198.51.100.7  | 192.0.2.177   |

  4. Using the amphora ID (1afabefd-ba09-49e1-8c39-41770aa25070) from the previous step, view amphora information.

    Example

    $ openstack loadbalancer amphora show 1afabefd-ba09-49e1-8c39-41770aa25070

    Sample output

    +-----------------+--------------------------------------+
| Field           | Value                                |
+-----------------+--------------------------------------+
| id              | 1afabefd-ba09-49e1-8c39-41770aa25070 |
| loadbalancer_id | 265d0b71-c073-40f4-9718-8a182c6d53ca |
| compute_id      | ba9fc1c4-8aee-47ad-b47f-98f12ea7b200 |
| lb_network_ip   | 198.51.100.7                         |
| vrrp_ip         | 192.0.2.36                           |
| ha_ip           | 192.0.2.177                          |
| vrrp_port_id    | 07dcd894-487a-48dc-b0ec-7324fe5d2082 |
| ha_port_id      | 94a12275-1505-4cdc-80c9-4432767a980f |
| cert_expiration | 2022-03-19T15:59:23                  |
| cert_busy       | False                                |
| role            | STANDALONE                           |
| status          | ALLOCATED                            |
| vrrp_interface  | None                                 |
| vrrp_id         | 1                                    |
| vrrp_priority   | None                                 |
| cached_zone     | nova                                 |
| created_at      | 2022-02-17T15:59:22                  |
| updated_at      | 2022-02-17T16:00:50                  |
| image_id        | 53001253-5005-4891-bb61-8784ae85e962 |
| compute_flavor  | 65                                   |
+-----------------+--------------------------------------+

  5. View the listener (listener1) details.

    Example

    $ openstack loadbalancer listener show listener1

    Sample output

    +-----------------------------+--------------------------------------+
| Field                       | Value                                |
+-----------------------------+--------------------------------------+
| admin_state_up              | True                                 |
| connection_limit            | -1                                   |
| created_at                  | 2022-02-17T16:00:59                  |
| default_pool_id             | 48f6664c-b192-4763-846a-da568354da4a |
| default_tls_container_ref   | None                                 |
| description                 |                                      |
| id                          | 5aaa67da-350d-4125-9022-238e0f7b7f6f |
| insert_headers              | None                                 |
| l7policies                  |                                      |
| loadbalancers               | 265d0b71-c073-40f4-9718-8a182c6d53ca |
| name                        | listener1                            |
| operating_status            | ONLINE                               |
| project_id                  | 52376c9c5c2e434283266ae7cacd3a9c     |
| protocol                    | HTTP                                 |
| protocol_port               | 80                                   |
| provisioning_status         | ACTIVE                               |
| sni_container_refs          | []                                   |
| timeout_client_data         | 50000                                |
| timeout_member_connect      | 5000                                 |
| timeout_member_data         | 50000                                |
| timeout_tcp_inspect         | 0                                    |
| updated_at                  | 2022-02-17T16:01:21                  |
| client_ca_tls_container_ref | None                                 |
| client_authentication       | NONE                                 |
| client_crl_container_ref    | None                                 |
| allowed_cidrs               | None                                 |
+-----------------------------+--------------------------------------+

  6. View the pool (pool1) and load-balancer members.

    Example

    $ openstack loadbalancer pool show pool1

    Sample output

    +----------------------+--------------------------------------+
| Field                | Value                                |
+----------------------+--------------------------------------+
| admin_state_up       | True                                 |
| created_at           | 2022-02-17T16:01:08                  |
| description          |                                      |
| healthmonitor_id     | 4b24180f-74c7-47d2-b0a2-4783ada9a4f0 |
| id                   | 48f6664c-b192-4763-846a-da568354da4a |
| lb_algorithm         | ROUND_ROBIN                          |
| listeners            | 5aaa67da-350d-4125-9022-238e0f7b7f6f |
| loadbalancers        | 265d0b71-c073-40f4-9718-8a182c6d53ca |
| members              | b92694bd-3407-461a-92f2-90fb2c4aedd1 |
|                      | 4ccdd1cf-736d-4b31-b67c-81d5f49e528d |
| name                 | pool1                                |
| operating_status     | ONLINE                               |
| project_id           | 52376c9c5c2e434283266ae7cacd3a9c     |
| protocol             | HTTP                                 |
| provisioning_status  | ACTIVE                               |
| session_persistence  | None                                 |
| updated_at           | 2022-02-17T16:01:21                  |
| tls_container_ref    | None                                 |
| ca_tls_container_ref | None                                 |
| crl_container_ref    | None                                 |
| tls_enabled          | False                                |
+----------------------+--------------------------------------+

  7. Verify HTTPS traffic flows across a load balancer whose listener is configured for HTTPS or TERMINATED_HTTPS protocols by connecting to the VIP address (192.0.2.177) of the load balancer.

    Tip

    Obtain the load-balancer VIP address by using the command, openstack loadbalancer show <load_balancer_name>.

    Example

    $ curl -v https://192.0.2.177 --insecure

    Sample output

    * About to connect() to 192.0.2.177 port 443 (#0)
*   Trying 192.0.2.177...
* Connected to 192.0.2.177 (192.0.2.177) port 443 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
* skipping SSL peer certificate verification
* SSL connection using TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
* Server certificate:
* 	subject: CN=www.example.com,O=Dis,L=Springfield,ST=Denial,C=US
* 	start date: Jan 15 09:21:45 2021 GMT
* 	expire date: Jan 15 09:21:45 2021 GMT
* 	common name: www.example.com
* 	issuer: CN=www.example.com,O=Dis,L=Springfield,ST=Denial,C=US
> GET / HTTP/1.1
> User-Agent: curl/7.29.0
> Host: 192.0.2.177
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Length: 30
<
* Connection #0 to host 192.0.2.177 left intact

Additional resources

12.2. Migrating a specific Load-balancing service instance

In some cases you must migrate a Load-balancing service instance (amphora). For example, if the host is being shut down for maintenance

Procedure

  1. Source your credentials file.

    Example

    $ source ~/overcloudrc

  2. Locate the ID of the amphora that you want to migrate. You need to provide the ID in a later step. 

    $ openstack loadbalancer amphora list

  3. To prevent the Compute scheduler service from scheduling any new amphorae to the Compute node being evacuated, disable the Compute node (compute-host-1).

    Note

    Values inside parentheses are sample values that are used in the example commands in this procedure. Substitute these sample values with ones that are appropriate for your site.

    Example

    $ openstack compute service set compute-host-1 nova-compute --disable

  4. Fail over the amphora by using the amphora ID (ea17210a-1076-48ff-8a1f-ced49ccb5e53) that you obtained.

    Example

    $ openstack loadbalancer amphora failover ea17210a-1076-48ff-8a1f-ced49ccb5e53

Additional resources

12.3. Using SSH to connect to load-balancing instances

Use SSH to log in to Load-balancing service instances (amphorae) when troubleshooting service problems.

It can be helpful to use Secure Shell (SSH) to log into running Load-balancing service instances (amphorae) when troubleshooting service problems.

Prerequisites

  • You must have the Load-balancing service (octavia) SSH private key.
  • You must have SSH enabled in the Load-balancing service configuration before you create the load balancer.

Procedure

  1. On the director node, start ssh-agent and add your user identity key to the agent: 

    $ eval $(ssh-agent -s)
$ ssh-add

  2. Source your credentials file.

    Example

    $ source ~/overcloudrc

  3. Determine the IP address on the load-balancing management network (lb_network_ip) for the amphora that you want to connect to: 

    $ openstack loadbalancer amphora list

  4. Use SSH to connect to the amphora: 

    $ ssh -A -t heat-admin@<controller_node_IP_address> ssh cloud-user@<lb_network_ip>

  5. When you are finished, close your connection to the amphora and stop the SSH agent: 

    $ exit

Additional resources

12.4. Showing listener statistics

Using the OpenStack Client, you can obtain statistics about the listener for a particular Red Hat OpenStack Platform (RHOSP) loadbalancer:

  • current active connections (active_connections).
  • total bytes received (bytes_in).
  • total bytes sent (bytes_out).
  • total requests that were unable to be fulfilled (request_errors).
  • total connections handled (total_connections).

Procedure

  1. Source your credentials file.

    Example

    $ source ~/overcloudrc

  2. View the stats for the listener (listener1).

    Note

    Values inside parentheses are sample values that are used in the example commands in this procedure. Substitute these sample values with ones that are appropriate for your site.

    Example

    $ openstack loadbalancer listener stats show listener1

    Tip

    If you do not know the name of the listener, enter the command loadbalancer listener list.

    Sample output

    +--------------------+-------+
| Field              | Value |
+--------------------+-------+
| active_connections | 0     |
| bytes_in           | 0     |
| bytes_out          | 0     |
| request_errors     | 0     |
| total_connections  | 0     |
+--------------------+-------+

Additional resources

12.5. Interpreting listener request errors

You can obtain statistics about the listener for a particular Red Hat OpenStack Platform (RHOSP) loadbalancer. For more information, see Section 12.4, “Showing listener statistics”.

One of the statistics tracked by the RHOSP loadbalancer, request_errors, is only counting errors that occurred in the request from the end user connecting to the load balancer. The request_errors variable is not measuring errors reported by the member server.

For example, if a tenant connects through the RHOSP Load-balancing service (octavia) to a web server that returns an HTTP status code of 400 (Bad Request), this error is not collected by the Load-balancing service. Loadbalancers do not inspect the content of data traffic. In this example, the loadbalancer interprets this flow as successful because it transported information between the user and the web server correctly.

The following conditions can cause the request_errors variable to increment:

  • early termination from the client, before the request has been sent.
  • read error from the client.
  • client timeout.
  • client closed the connection.
  • various bad requests from the client.

Additional resources