How to write a command to be executed in the docker compose?

Question

I am kind of new to docker and docker compose. I am using 20.10.12 version of docker and 2.9.0 of portainer. My aim is to do the docker compose for elasticSearch to deploy it in portainer but I get a problem that the memory given is not enough. After looking through other questions I found that I could execute the following bash command to assign a bigger limit to the VM memory

sysctl -w vm.max_map_count=262144

So my .yml is like this:

version: "3.8"

services:
  command: >
      bash -c ' sysctl -w vm.max_map_count=262144'
  master1:
    image: docker.elastic.co/elasticsearch/elasticsearch:8.0.0
    environment:                  
      node.name: "master1"
    ulimits:
        memlock:
          soft: -1
          hard: -1        
    deploy:
      endpoint_mode: dnsrr         
      mode: "replicated"
      replicas: 1
      resources:
        limits:
          memory: 4G

The problem is that when I try to deploy this compose, it says "services.command must be a mapping".

I think that problem is raised when then indentation is not correct but I think in my case is indented correctly.

Answer 1

vm.max_map_count must be set on the host, and not in the docker container. Set it as described in this official doc.