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Command: alloc logs

Alias: nomad logs

The alloc logs command displays the log of a given task.

Usage

nomad alloc logs [options] <allocation> <task>

This command streams the logs of the given task in the allocation. If the allocation is only running a single task, the task name can be omitted. Optionally, the -job option may be used in which case a random allocation from the given job will be chosen.

When ACLs are enabled, this command requires a token with the read-logs, read-job, and list-jobs capabilities for the allocation's namespace.

General Options

  • -address=<addr>: The address of the Nomad server. Overrides the NOMAD_ADDR environment variable if set. Defaults to http://127.0.0.1:4646.

  • -region=<region>: The region of the Nomad server to forward commands to. Overrides the NOMAD_REGION environment variable if set. Defaults to the Agent's local region.

  • -namespace=<namespace>: The target namespace for queries and actions bound to a namespace. Overrides the NOMAD_NAMESPACE environment variable if set. If set to '*', job and alloc subcommands query all namespacecs authorized to user. Defaults to the "default" namespace.

  • -no-color: Disables colored command output. Alternatively, NOMAD_CLI_NO_COLOR may be set.

  • -ca-cert=<path>: Path to a PEM encoded CA cert file to use to verify the Nomad server SSL certificate. Overrides the NOMAD_CACERT environment variable if set.

  • -ca-path=<path>: Path to a directory of PEM encoded CA cert files to verify the Nomad server SSL certificate. If both -ca-cert and -ca-path are specified, -ca-cert is used. Overrides the NOMAD_CAPATH environment variable if set.

  • -client-cert=<path>: Path to a PEM encoded client certificate for TLS authentication to the Nomad server. Must also specify -client-key. Overrides the NOMAD_CLIENT_CERT environment variable if set.

  • -client-key=<path>: Path to an unencrypted PEM encoded private key matching the client certificate from -client-cert. Overrides the NOMAD_CLIENT_KEY environment variable if set.

  • -tls-server-name=<value>: The server name to use as the SNI host when connecting via TLS. Overrides the NOMAD_TLS_SERVER_NAME environment variable if set.

  • -tls-skip-verify: Do not verify TLS certificate. This is highly not recommended. Verification will also be skipped if NOMAD_SKIP_VERIFY is set.

  • -token: The SecretID of an ACL token to use to authenticate API requests with. Overrides the NOMAD_TOKEN environment variable if set.

Logs Options

  • -stderr: Display stderr logs.

  • -verbose: Display verbose output.

  • -job: Use a random allocation from the specified job, preferring a running allocation.

  • -f: Causes the output to not stop when the end of the logs are reached, but rather to wait for additional output.

  • -tail: Show the logs contents with offsets relative to the end of the logs. If no offset is given, -n is defaulted to 10.

  • -n: Sets the tail location in best-efforted number of lines relative to the end of the logs.

  • -c: Sets the tail location in number of bytes relative to the end of the logs.

Note that the -no-color option applies to Nomad's own output. If the task's logs include terminal escape sequences for color codes, Nomad will not remove them.

Examples

$ nomad alloc logs eb17e557 redis
foobar
baz
bam

$ nomad alloc logs -stderr eb17e557 redis
[ERR]: foo
[ERR]: bar

$ nomad alloc logs -job example
[ERR]: foo
[ERR]: bar

$ nomad alloc logs -tail -n 2 eb17e557 redis
foobar
baz

$ nomad alloc logs -tail -f -n 3 eb17e557 redis
foobar
baz
bam
<blocking>

Using Job ID instead of Allocation ID

Setting the -job flag causes a random allocation of the specified job to be selected. Nomad will prefer to select a running allocation ID for the job, but if no running allocations for the job are found, Nomad will use a dead allocation.

nomad alloc logs -job <job-id> <task>

Choosing a specific allocation is useful for debugging issues with a specific instance of a service. For other operations using the -job flag may be more convenient than looking up an allocation ID to use.