Manually Validate Server Health

It is often helpful to validate the response of a server while troubleshooting reasons a server may be marked down. The challenge is to ensure the test is from a specific Avi Service Engine, using the same tenant, network, and IP address. SEs have multiple network stacks, one for the control plane which uses Linux, and a second for the data plane. Simply logging into an SE and pinging a server will go out the management port and IP address, which may route through different infrastructure than the SE data plane.

For more info on health monitoring servers see:

 

Prerequisites

  1. Determine the IP address of the Service Engine hosting the virtual service.
  2. SSH into the Avi Controller
  3. Log into the Avi shell
    shell

VMware - No Tenants

  1. Connect to a Service Engine's Linux shell:
    : > attach serviceengine 10.10.25.28
  2. Validate the current namespace:
    admin@10-10-25-28:~$ ip netns
    Usual output is avi_ns1, which is the default namespace.
  3. Execute a static health check from this namespace. See examples at the end of this article.

VMware - Multiple Tenants

For multiple tenants on VMware, Avi Vantage does not create VRFs/namespaces by default.

  1. Attach to the Service Engine Linux shell:
    : > attach serviceengine 10.10.25.28
  2. Execute a static health check. See examples at the end of this article.

Multiple Tenants with VRF (Provider Mode)

  1. Find the namespace/VRF for the pool server:
    : > show pool p1 detail  | grep vrf_id
     | vrf_id   | 2
    In this case, the vrf_id is 2, and the namespace is avi_ns2.
    This information can also be obtained from:
    : > show serviceengine 10.10.25.28 vnicdb
  2. If there are multiple SEs, find the vrf-id on the specific SE:
    show pool p1 detail | filter disable_aggregate se  se_ref 10.10.25.28
    | vrf_id   | 2
  3. Attach to the Service Engine Linux shell:
    : > attach serviceengine 10.10.25.28
  4. Execute a static health check from this namespace. See examples at the end of this article.

Bare Metal / Linux Cloud

For bare-metal Linux clouds, there are no namespaces, reducing the necessary steps.

  1. Attach to the Service Engine Linux shell:
    : > attach serviceengine 10.10.25.28
  2. Execute a static health check. See examples at the end of this article.

Common Manual Server Checks

Ping:

root@test-se2:~# ip netns exec avi_ns1 ping 10.90.15.62
 PING 10.90.15.62 (10.90.15.62) 56(84) bytes of data.
 64 bytes from 10.90.15.62: icmp_seq=1 ttl=64 time=26.8 ms

Curl:

root@test-se2:~# ip netns exec avi_ns1 curl 10.90.15.62
 curl:  Failed to connect to 10.90.15.62 port 80: Connection refused

 root@test-se2:~# ip netns exec avi_ns1 curl 10.90.15.62:8000Welcome - Served from port 80!

Note: This step is not necessary when the SE is on a Docker + bare-metal setup and the Docker container itself exists in a namespace.

Updated: 2018-01-18 11:22:54 +0000