ID: swarm

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The Swarm plugin enables nodes to join a nearby Jenkins master, thereby forming an ad-hoc cluster. This plugin makes it easier to scale a Jenkins cluster by spinning up and tearing down new nodes.

This plugin consists of two pieces:

  1. A self-contained client that can join an existing Jenkins master.
  2. A plugin that needs to be installed on Jenkins master to accept Swarm clients.

With the Swarm client, a person who is willing to contribute some of his computing power to the cluster just needs to run a virtual machine with the Swarm client and the cluster gets an additional agent. Because the Swarm client is running on a separate VM, there is no need to worry about the builds/tests interfering with the host system or altering its settings unexpectedly.

Getting started

  1. Install the Swarm plugin from the Update Center.
  2. Download the Swarm client.
  3. Run the Swarm client with java -jar path/to/swarm-client.jar. There are no required command-line options; run with the -help option to see the available options.


Available options

$ java -jar swarm-client.jar -help

Name Description
-deleteExistingClients Delete any existing agent with the same name. (default: false)
-description VAL Description to be put on the agent.
-disableClientsUniqueId Disable client's unique ID. (default: false)
-disableSslVerification Disable SSL verification in the HTTP client. (default: false)
-disableWorkDir Disable Remoting working directory support and run the agent in legacy mode. (default: false)
-e (--env) An environment variable to be defined on this agent. It is specified as 'key=value'. Multiple variables are allowed.
-executors N Number of executors (default: number of CPUs)
-failIfWorkDirIsMissing Fail if the requested Remoting working directory or internal directory is missing. (default: false)
-fsroot FILE Remote root directory. (default: .)
-help (--help, -h) Show the help screen (default: false)
-internalDir FILE The name of the directory within the Remoting working directory where files internal to Remoting will be stored.
-jar-cache FILE Cache directory that stores JAR files sent from the master.
-labels VAL Whitespace-separated list of labels to be assigned for this agent. Multiple options are allowed.
-labelsFile VAL File location with space delimited list of labels. If the file changes, the client is restarted.
-master VAL The complete target Jenkins URL like 'http://server:8080/jenkins/'.
-maxRetryInterval N Max time to wait before retry in seconds. Default is 60 seconds. (default: 60)
-mode MODE The mode controlling how Jenkins allocates jobs to agents. Can be either 'normal' (use this node as much as possible) or 'exclusive' (only build jobs with label expressions matching this node). Default is 'normal'. (default: normal)
-name VAL Name of the agent.
-noRetryAfterConnected Do not retry if a successful connection gets closed. (default: false)
-password VAL The Jenkins user API token or password.
-passwordEnvVariable VAL Environment variable containing the Jenkins user API token or password.
-passwordFile VAL File containing the Jenkins user API token or password.
-pidFile VAL File to write PID to. The client will refuse to start if this file exists and the previous process is still running.
-prometheusPort N If defined, then start an HTTP service on this port for Prometheus metrics. (default: -1)
-retry N Number of retries before giving up. Unlimited if not specified. (default: -1)
-retryBackOffStrategy RETRY_BACK_OFF_STRATEGY The mode controlling retry wait time. Can be either 'none' (use same interval between retries) or 'linear' (increase wait time before each retry up to maxRetryInterval) or 'exponential' (double wait interval on each retry up to maxRetryInterval). Default is 'none'. (default: NONE)
-retryInterval N Time to wait before retry in seconds. Default is 10 seconds. (default: 10)
-sslFingerprints VAL Whitespace-separated list of accepted certificate fingerprints (SHA-256/Hex), otherwise system truststore will be used. No revocation, expiration or not yet valid check will be performed for custom fingerprints! Multiple options are allowed. (default: )
-t (--toolLocation) A tool location to be defined on this agent. It is specified as 'toolName=location'.
-tunnel VAL Connect to the specified host and port, instead of connecting directly to Jenkins. Useful when connection to Jenkins needs to be tunneled. Can be also HOST: or :PORT, in which case the missing portion will be auto-configured like the default behavior
-username VAL The Jenkins username for authentication.
-webSocket Connect using the WebSocket protocol. (default: false)
-workDir FILE The Remoting working directory where the JAR cache and logs will be stored.


Report issues and enhancements in the Jenkins issue tracker. Use the swarm-plugin component in the JENKINS project.


Refer to our contribution guidelines.

ArchivesGet past versions
Version: 3.24
Requires Jenkins 2.176.4
Installs: 7,167
Basil Crow
Kohsuke Kawaguchi
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