Consul Debug

Command: consul debug

The consul debug command monitors a Consul agent for the specified period of time, recording information about the agent, cluster membership, and environment to an archive written to the current directory.

Providing support for complex issues encountered by Consul operators often requires a large amount of debugging information to be retrieved. This command aims to shortcut that coordination and provide a simple workflow for accessing data about Consul agent, cluster membership, and environment to enable faster isolation and debugging of issues.

This command requires an operator:read ACL token in order to retrieve the data from the target agent, if ACLs are enabled.

If the command is interrupted, as it could be given a long duration but require less time than expected, it will attempt to archive the current captured data.

Security and Privacy

By default, ACL tokens, private keys, and other sensitive material related to Consul is sanitized and not available in this archive. However, other information about the environment the target agent is running in is available in plain text within the archive.

It is recommended to validate the contents of the archive and redact any material classified as sensitive to the target environment, or use the -capture flag to not retrieve it initially.

Additionally, we recommend securely transmitting this archive via encryption or otherwise.

Usage

Usage: consul debug [options]

By default, the debug command will capture an archive at the current path for all targets for 2 minutes.

API Options

-ca-file=<value> - Path to a CA file to use for TLS when communicating with Consul. This can also be specified via the CONSUL_CACERT environment variable.
-ca-path=<value> - Path to a directory of CA certificates to use for TLS when communicating with Consul. This can also be specified via the CONSUL_CAPATH environment variable.
-client-cert=<value> - Path to a client cert file to use for TLS when verify_incoming is enabled. This can also be specified via the CONSUL_CLIENT_CERT environment variable.
-client-key=<value> - Path to a client key file to use for TLS when verify_incoming is enabled. This can also be specified via the CONSUL_CLIENT_KEY environment variable.
-http-addr=<addr> - Address of the Consul agent with the port. This can be an IP address or DNS address, but it must include the port. This can also be specified via the CONSUL_HTTP_ADDR environment variable. In Consul 0.8 and later, the default value is http://127.0.0.1:8500, and https can optionally be used instead. The scheme can also be set to HTTPS by setting the environment variable CONSUL_HTTP_SSL=true. This may be a unix domain socket using unix:///path/to/socket if the agent is configured to listen that way.
-tls-server-name=<value> - The server name to use as the SNI host when connecting via TLS. This can also be specified via the CONSUL_TLS_SERVER_NAME environment variable.
-token=<value> - ACL token to use in the request. This can also be specified via the CONSUL_HTTP_TOKEN environment variable. If unspecified, the query will default to the token of the Consul agent at the HTTP address.
-token-file=<value> - File containing the ACL token to use in the request instead of one specified via the -token argument or CONSUL_HTTP_TOKEN environment variable. This can also be specified via the CONSUL_HTTP_TOKEN_FILE environment variable.

Command Options

-duration - Optional, the total time to capture data for from the target agent. Must be greater than the interval and longer than 10 seconds. Defaults to 2 minutes.
-interval - Optional, the interval at which to capture dynamic data, such as heap and metrics. Must be longer than 5 seconds. Defaults to 30 seconds.
-capture - Optional, can be specified multiple times for each capture target and will only record that information in the archive.
-output - Optional, the full path of where to write the directory of data and resulting archive. Defaults to the current directory.
-archive - Optional, if the tool show archive the directory of data into a compressed tar file. Defaults to true.

Capture Targets

The -capture flag can be specified multiple times to capture specific information when debug is running. By default, it captures all information.

Target	Description
`agent`	Version and configuration information about the agent.
`host`	Information about resources on the host running the target agent such as CPU, memory, and disk.
`members`	A list of all the WAN and LAN members in the cluster.
`metrics`	Metrics from the in-memory metrics endpoint in the target, captured at the interval.
`logs`	`DEBUG` level logs for the target agent, captured for the duration.
`pprof`	Golang heap, CPU, goroutine, and trace profiling. CPU profile is captured for `duration` in a single file, trace is captured for a single `interval`, while heap and goroutine are separate snapshots for each `interval`. This information is not retrieved unless `enable_debug` is set to `true` on the target agent or ACLs are enable and an ACL token with `operator:read` is provided.

Examples

This command can be run from any host with the Consul binary, but requires network access to the target agent in order to retrieve data. Once retrieved, the data is written to the the specified path (defaulting to the current directory) on the host where the command runs.

By default the command will capture all available data from the default agent address on loopback for 2 minutes at 30 second intervals.

$ consul debug
...

In this example, the archive is collected from a different agent on the network using the standard Consul CLI flag to change the API address.

$ consul debug -http-addr=10.0.1.10:8500
...

The capture flag can be specified to only record a subset of data about the agent and environment.

$ consul debug -capture agent -capture host -capture logs
...

The duration of the command and interval of capturing dynamic information (such as metrics) can be specified with the -interval and -duration flags.

$ consul debug -interval=15s -duration=1m
...