CODEWITHSUNDEEP
network-programmingdocker-composeyamlexternal
Kim Le jonc
Kim Le jonc

Reputation: 33

Docker-Compose file has yaml.scanner.ScannerError : mapping values are not allowed here

My objective is to use 1 bridge network in docker for all my docker-compose on the same host, for all my domains.

I have configured 3 yml file for my docker-compose infrastructure and I'm using 1 external bridge network dockerprometheus_back-tier for all of them. One YAML file for reverse proxy (traefik) and one YAML file for each domain name (2 files).

Each time I'm trying to stop & start the last YAML with the command docker-compose -f mail.yml down && docker-compose -f mail.yml up -d, I got :

yaml.scanner.ScannerError: mapping values are not allowed here

After commenting most of the commands in the yml 3, I understand that the problem is when I add the line name: dockerprometheus_back-tier

But in the 2 other yml files, I already did exactly the same configuration to use this network and the yaml processor doesn't complain.

YAML 1

version: '3'

networks:
  internal:
    external: false
  prometheus:
    external: true
      name: dockerprometheus_back-tier

YAML 2

version: '3'

networks:
  onlyinternal:
    driver: bridge
    external: false
  prometheus:
    external: true
      name: dockerprometheus_back-tier



docker network ls
04e3348408c4        dockerprometheus_back-tier    bridge              local

I applied dos2unix to clean the encoding on the YAML 3 but doesn't change anything. I made a copy directly of the YAML 3, keeping the first lines, and trying to start it but it failed too with same error. Is there a limitation in docker to use 3 times the same bridge network from external files? How to solve it?

Docker version 18.09.3, build 774a1f4 , CentOS Linux release 7.6.1810 (Core)

YAML 3:

version: '3'

networks:
  mail_network:
    driver: bridge
    external: false
  prometheus:
    external: true
      name: dockerprometheus_back-tier

Upvotes: 2

Views: 3704

Answers (1)

Anthon
Anthon

Reputation: 76599

All three YAML documents you present have the same problem and are all invalid.

As value for the key external you have a multi-line unquoted scalar 

true name: dockerprometheus_back-tier

within an unquoted scalar you cannot have a value indicator followed by whitespace as this might indicate a new key. Either quote the multi-line scalar:

networks:
  mail_network:
    driver: bridge
    external: false
  prometheus:
    external: "true
      name: dockerprometheus_back-tier"

Or if name should be a key at the same level as external, make sure it is indented as such:

networks:
  mail_network:
    driver: bridge
    external: false
  prometheus:
    external: true
    name: dockerprometheus_back-tier

You can have something like the following in YAML:

  prometheus:
    external:
      name: dockerprometheus_back-tier

but of course a key cannot both have, as value, a scalar node (true) and a mapping node ('name: dockerprometheus_back-tier')

Upvotes: 1

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