I'm trying to add healthcheck for my docker app by grep the curl result. When i run into docker container:

curl -sS http://nginx | grep -c works > /dev/null 
echo $?

I getting 0 and everything seems fine, but if I'm trying to add it into docker-compose

version: "3.8"

services:
  php:
    build: .
    volumes:
     - ./www:/var/www
    healthcheck:
     test: ["CMD", "curl", "-sS", "http://nginx | grep", "-c", "works > /dev/null"]
     interval: 5s
     timeout: 5s
     retries: 5
  nginx:
    image: "nginx:latest"
    ports:
     - "8080:80"
    volumes:
     - ./nginx:/etc/nginx/conf.d
     - ./www:/var/www
    links:
     - php

and check it by docker-compose ps it has status "unhealthy". What am I doing wrong?

CodePudding user response：

There are two problems here:

1. You split your arguments in a weird way - "http://nginx | grep" and "works > /dev/null" don't make much sense and will be passed literally to curl

2. You are using a format in test which does not call the shell - as such, shell fetures like | and > won't work since they need to be interpreted by your shell. You need to either pass test as a string, or use the CMD-SHELL form:

   healthcheck:
     test: curl -sS http://nginx | grep -c works > /dev/null
     interval: 5s
     timeout: 5s
     retries: 5

Or:

    healthcheck:
     test: ["CMD-SHELL", "curl -sS http://nginx | grep -c works > /dev/null"]
     interval: 5s
     timeout: 5s
     retries: 5

For more information on healthcheck, you can read about it in the compose file reference.

CodePudding user response：

Healthcheck can be specified either in shell form, or as an EXEC array (like you have done).

The exec array doesn't support most shell functionality, like using pipes.

I expect it will work fine if you specify it in shell form. I.e.

    healthcheck:
     test: curl -sS http://nginx | grep -c works > /dev/null

Or wrap it in ["CMD", "/bin/sh", "-c", "curl -sS ..."].

CodePudding user response：

I guess your problem is the pipe operator. Afaik you also dont need the CMD.

You can try it like this.

test: curl -sS http://nginx | grep -c works > /dev/null

You can also check what your health check is actually doing.

docker inspect myproject_php_1 --format \
  '{{range .State.Health.Log}}{{.End}} | Exit Code: {{.ExitCode}} | {{.Output}}{{end}}'