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miren sandbox exec

Open interactive shell in an existing sandbox

This command connects to an existing sandbox and runs a command inside it. Unlike miren app run which creates a new ephemeral sandbox, this connects to a sandbox that's already running (typically one serving production traffic).

Letting miren pick the sandbox​

Pass --app and you don't need a sandbox ID at all — miren picks one of that app's running sandboxes for you:

miren sandbox exec --app myapp
miren sandbox exec --app myapp -- ls -la /app

The choice is random among the sandboxes that qualify, so with more than one running you may land somewhere different each time. When there was more than one to choose from, miren names the one it picked — on a terminal only, so that piping or redirecting output never mixes miren's chatter into the sandbox's own.

An app with several services gets its web service, and only that one. If no web instance is up, miren says so rather than substituting a worker, since landing in the wrong kind of process is worse than being told to try again. Use --service to ask for a different one:

miren sandbox exec --app myapp --service worker -- ps aux

Within the service you asked for, miren prefers sandboxes running your app's current version, so a command run during a deploy won't drop you into the version you just replaced. That one is a preference rather than a rule: a failed deploy leaves the current version pointing at something that never came up while the previous instances keep serving traffic, and refusing those would lock you out of a shell exactly when you need one.

Put -- before your command

Anything after -- is passed to the sandbox untouched. Without it, a flag meant for your command is read as a flag for miren — miren sandbox exec --app myapp ls -la fails on -l, and a -h anywhere before -- prints this help instead of running anything.

Finding sandbox IDs​

To target a specific sandbox instead, use miren sandbox list to find its ID:

$ miren sandbox list
ID                          APP       SERVICE   STATUS    NODE
sandbox/myapp-web-abc123    myapp     web       RUNNING   node-1
sandbox/myapp-web-def456    myapp     web       RUNNING   node-2
This is a live instance

When you exec into a production sandbox, you're connecting to a live instance that may be serving traffic. Be careful with commands that could affect the running application.

Use app run to stay out of the way

For debugging or one-off tasks without affecting production, use miren app run to create an isolated ephemeral sandbox instead.

Usage​

miren sandbox exec [args...] [flags]

Flags​

  • --app, -a — Pick a running sandbox belonging to this app
  • --cluster, -C — Cluster name
  • --config — Path to the config file
  • --id, -i — Sandbox ID
  • --service — With --app, restrict the choice to one service (default: web)

Global Options​

  • --options — Path to file containing options
  • --server-address — Server address to connect to (default: 127.0.0.1:8443)
  • --verbose, -v — Enable verbose output

Examples​

Open a shell in a running sandbox:

miren sandbox exec sb_abc123

Run a command in a sandbox:

miren sandbox exec sb_abc123 -- ls -la /app

Let miren pick a running sandbox for an app:

miren sandbox exec --app myapp

Run a command in one of an app's worker sandboxes:

miren sandbox exec --app myapp --service worker -- ps aux

See also​