Let's say your Kong application has been deployed to OpenShift. The oc get pods command can be used to display the kong pods.

oc get pods -n kong

Something like this should be returned.

NAME                                  READY   STATUS    RESTARTS   AGE
grafana-0                             2/2     Running   0          27d
kong-1.3.0.2-6c789dccf5-4w5sw         1/1     Running   0          27d
kong-1.3.0.2-6c789dccf5-fc4nr         1/1     Running   0          27d
kong-1.3.0.2-6c789dccf5-n5f45         1/1     Running   0          27d
kong-admin-1.3.0.2-5d7c89d4bb-4gg4g   1/1     Running   0          27d
postgres-67b6d87679-d76d5             1/1     Running   14         27d
prom-0                                4/4     Running   12         27d
redis-574787997b-5jbpv                2/2     Running   6          27d

In this example, the kong health command is issued in the kong-1.3.0.2-6c789dccf5-4w5sw pod to determine if Kong is healthy.

oc exec kong-1.3.0.2-6c789dccf5-4w5sw -n kong -- kong health

If Kong is healthy, something like this should be returned.

nginx.......running

Kong is healthy at /usr/local/kong

If Kong is not healthy, something like this should be returned.

Kong is not running at /usr/local/kong

Under the hood, the kong command line tool (/usr/local/bin/kong) is an OpenResty script.

#!/usr/bin/env /usr/local/openresty/bin/resty
setmetatable(_G, nil)
pcall(require, "luarocks.loader")
package.path = (os.getenv("KONG_LUA_PATH_OVERRIDE") or "") .. "./?.lua;./?/init.lua;" .. package.path
require("kong.cmd.init")(arg)

This OpenResty script requires kong.cmd.init, which would be a file along the lines of /usr/local/share/lua/5.1/kong/cmd/init.lua. When the kong command is invokes with the "health" flag, this tells the kong/cmd/init.lua file to call the /usr/local/share/lua/5.1/kong/cmd/health.lua file.

The kong/cmd/health.lua file will check if the Kong services are running.