EXRM: Unknown command command

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1

Hey everyone,

I’ve encountered a problem which I’m having some trouble solving. I’m working on an older Elixir/Phoenix codebase that uses EXRM for releases and I discovered yesterday that the migration task isn’t working in AWS. I’ve logged into the EC2 instance and from there have connected to a docker container where the release folders are. When I run this command: app/bin/backend command Elixir.Release.Tasks migrate I get the following error:

Usage: backend COMMAND [ARGS]

The known commands are:

    start          Starts the system
    start_iex      Starts the system with IEx attached
    daemon         Starts the system as a daemon
    daemon_iex     Starts the system as a daemon with IEx attached
    eval "EXPR"    Executes the given expression on a new, non-booted system
    rpc "EXPR"     Executes the given expression remotely on the running system
    remote         Connects to the running system via a remote shell
    restart        Restarts the running system via a remote command
    stop           Stops the running system via a remote command
    pid            Prints the operating system PID of the running system via a remote command
    version        Prints the release name and version to be booted

ERROR: Unknown command command

I suspect that I didn’t install everything for my application correctly but I’m flummoxed with how to fix it. Any help would be appreciated.

Nick

2

Should command be replaced by the comand you wish to use, e.g.: app/bin/backend eval "EXPR" where "EXPR" is the expression you want to execute?

3

I was following this example to get it working: Running migration in an Exrm release « Plataformatec Blog

So I took it as literally meaning “command” as the second argument of app/bin/backend command Elixir.Release.Tasks migrate

4

You can either go back to pre 1.10 elixir to continue to use exrm, or to use the newer way of migration, as per @muelthe has suggested. The official latest doc on this is here

5

Thanks @derek-zhou , @muelthe

I ended getting it working with this: docker exec -it fc25b2987f22 "/app/bin/backend" "rpc" "Release.Tasks.migrate" based on the docs. I didn’t know they changed it after 1.10.

1 Like
6

The command works but I have a weird issue. I run it in the context of docker:

docker exec -it 7e4398fc38c4 app/bin/backend "rpc" "Release.Tasks.migrate"

However if I run it a second time I get this error:
RPC failed with reason :nodedown. Then the container dies and it spawns a new one.

Does anyone know why this could be?