SlickNik commented on a change in pull request #278: Fixes #268: Setup fails
when swarmmanager enabled
URL: https://github.com/apache/fluo-muchos/pull/278#discussion_r320103606
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File path: ansible/docker.yml
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@@ -48,5 +48,5 @@
changed_when: "'active' not in swarm_status.stdout_lines"
- name: join worker to swarm
shell: >
- docker swarm join --token={{ swarm_token }} {{ manager_ip }}:2377
+ docker swarm leave || true && docker swarm join --token={{
swarm_token_stdout }} {{ manager_ip }}:2377
Review comment:
`docker swarm join` doesn't have a `--force` flag, and errors out if the
node is already part of a swarm (so subsequent runs of the ansible state fail
since this isn't idempotent). To make this idempotent, we issue a `leave`
followed by a `join`. However `leave` fails with a non-zero exit code when the
node isn't already part of a swarm failing the execution of the entire shell
section. The `|| true` here basically tells the shell to ignore the exit code
of `docker swarm leave` and continue executing the rest. `;` wouldn't work here
since it just joins the two commands together, and the shell still errors when
the first command before the `;` exits with a non-zero exit code. The other
alternative here would be to explicitly disable the shell's exit code checking
for the `docker swarm leave` command (i.e. something like `set +e; docker swarm
leave; set -e; ...`), but I slightly prefer the `|| true` variant for the sake
of brevity.
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