See presentation slides from Jenkins World 2018.
Join our Jenkins Configuration as Code office hours meeting scheduled for every second Wednesday. Use the Hangout on Air link from our Gitter chat channel. As an alternative, use the link from the invitation. See previous meeting minutes.
Setting up Jenkins is a complex process, as both Jenkins and its plugins require some tuning and configuration,
with dozens of parameters to set within the web UI manage
section.
Experienced Jenkins users rely on groovy init scripts to customize Jenkins and enforce desired state. Those scripts directly invoke Jenkins API and as such can do everything (at your own risk). But they also require you know Jenkins internals, and are confident in writing groovy scripts on top of Jenkins API.
The Configuration as Code plugin has been designed as an opinionated way to configure Jenkins based on human-readable declarative configuration files. Writing such a file should be feasible without being a Jenkins expert, just translating into code a configuration process one is used to executing in the web UI.
This plugin aims to replace above user interface based configuration with the below text based configuration.
jenkins:
securityRealm:
ldap:
configurations:
- groupMembershipStrategy:
fromUserRecord:
attributeName: "memberOf"
inhibitInferRootDN: false
rootDN: "dc=acme,dc=org"
server: "ldaps://ldap.acme.org:1636"
In addition, we want to have a well documented syntax file, and tooling to assist in writing and testing, so end users have full guidance in using this tool set and do not have to search for examples on the Internet.
First, start a Jenkins instance with the Configuration as Code plugin installed.
- Those running Jenkins as a Docker container (and maybe also pre-installing plugins), do include Configuration as Code plugin.
Second, the plugin looks for the CASC_JENKINS_CONFIG
environment variable. The variable can point to any of the following:
- Path to a folder containing a set of config files. For example,
/var/jenkins_home/casc_configs
. - A full path to a single file. For example,
/var/jenkins_home/casc_configs/jenkins.yaml
. - A URL pointing to a file served on the web. For example,
https://acme.org/jenkins.yaml
.
If CASC_JENKINS_CONFIG
points to a folder, the plugin will recursively traverse the folder to find file (suffix with .yml,.yaml,.YAML,.YML), but doesn't contain hidden files or hidden subdirectories. It doesn't follow symbolic links.
If you do not set the CASC_JENKINS_CONFIG
environment variable, the plugin will
default to looking for a single config file in $JENKINS_ROOT/jenkins.yaml
.
If everything was setup correctly, you should now be able to browse the Configuration as Code page with Manage Jenkins
-> Configuration as Code
.
Prerequisites: Java, Maven & IntelliJ IDEA
-
Ensure Java 8 is available. There are unresolved issues with Java 10/11 as of October 24, 2018.
/usr/libexec/java_home
/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home
- If Java 11 is selected by default, check other available Java version below.
/usr/libexec/java_home --verbose
Matching Java Virtual Machines (3): 11.0.1, x86_64: "Java SE 11.0.1" /Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home 10.0.2, x86_64: "Java SE 10.0.2" /Library/Java/JavaVirtualMachines/jdk-10.0.2.jdk/Contents/Home 1.8.0_192, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_192.jdk/Contents/Home /Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home
- Use the alternate Java 8.
export JAVA_HOME=`/usr/libexec/java_home -v 1.8` echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.8.0_192.jdk/Contents/Home
-
Ensure Maven is included in the PATH environment variable.
export PATH=$PATH:/path/to/apache-maven-x.y.z/bin
- Open the root directory of this project in IntelliJ IDEA.
- If you are opening the first time, wait patiently while project dependencies are being downloaded.
- Click
Run
in the menu. SelectEdit Configurations
in the menu item. - Click
Add New Configuration
(+
) in the top left of the shown dialog. SelectMaven
. - Under
Parameters
tab group,Working directory:
is/path/to/configuration-as-code-plugin/plugin
. - Under
Parameters
tab group,Command line:
ishpi:run
. - Verify that IntelliJ IDEA is not using bundled maven.
- Click
File
->Preferences...
->Build, Execution, Deployment
->Build Tools
->Maven
. Maven home directory:
has/path/to/apache-maven-x.y.z
value, notBundled (Maven 3)
.
- Click
- Open http://localhost:8080/jenkins/configuration-as-code/ to test the plugin locally.
- Go into the
plugin
child directory under the root directory of this project. - Use the below commands.
export JAVA_HOME=`/usr/libexec/java_home -v 1.8`
export PATH=$PATH:/path/to/apache-maven-x.y.z/bin
mvn hpi:run
...
INFO: Jenkins is fully up and running
- Open http://localhost:8080/jenkins/configuration-as-code/ to test the plugin locally.
When configuring the first Jenkins instance, browse the examples shown in the demos
directory of this repository. If you have a plugin that does not have an example, consult the reference
help document. Click the Documentation
link at the bottom of the Configuration as Code page.
If you want to configure a specific plugin, search the page for the name of the plugin. The page will
show you which root element belongs to the configuration. Most installed plugins belong under the unclassified
root
element.
This configuration file includes root entries for various components of your primary Jenkins installation. The jenkins
one is for the root Jenkins object, and other ones are for various global configuration elements.
jenkins:
securityRealm:
ldap:
configurations:
- groupMembershipStrategy:
fromUserRecord:
attributeName: "memberOf"
inhibitInferRootDN: false
rootDN: "dc=acme,dc=org"
server: "ldaps://ldap.acme.org:1636"
nodes:
- permanent:
name: "static-agent"
remoteFS: "/home/jenkins"
launcher:
jnlp:
slaveAgentPort: 50000
agentProtocols:
- "jnlp2"
tool:
git:
installations:
- name: git
home: /usr/local/bin/git
unclassified:
mailer:
adminAddress: [email protected]
replyToAddress: [email protected]
# Note that this does not work right now
#smtpHost: smtp.acme.org
smtpPort: 4441
credentials:
system:
domainCredentials:
credentials:
- certificate:
scope: SYSTEM
id: ssh_private_key
keyStoreSource:
fileOnMaster:
keyStoreFile: /docker/secret/id_rsa
Also see demos folder with various samples.
The configuration file format depends on the version of jenkins-core and installed plugins. Documentation is generated from a live instance, as well as a JSON schema you can use to validate configuration file with your favourite YAML tools.
Currently, you can provide initial secrets to JCasC that all rely on <key,value>
substitution of strings in the configuration. For example, Jenkins: "${some_var}"
. Default variable substitution
using the :-
operator from bash
is also available. For example, key: "${VALUE:-defaultvalue}"
will evaluate to defaultvalue
if $VALUE
is unset. To escape a string from secret interpolation, put ^
in front of the value. For example, Jenkins: "^${some_var}"
will produce the literal Jenkins: "${some_var}"
.
We can provide these initial secrets in the following ways:
- Using environment variables.
- Using docker-secrets, where files on path
/run/secrets/${KEY}
will be replaced by${KEY}
in the configuration. The base folder/run/secrets
can be overridden by setting the environment variableSECRETS
. So this can be used as a file based secret, and not just docker secrets. - Using Kubernetes secrets, logic is the same as for docker-secrets. The secret needs to be mounted as a file to
/run/secrets/
, and then the filename can be used as the KEY. For example:
apiVersion: v1
kind: Secret
metadata:
name: secret-name
data:
filename: {{ "encoded string" | b64enc }}
can be used as:
- credentials:
- string:
id: "cred-id"
secret: ${filename}
- Using Vault, see below.
Jenkins configurations might include property definitions, e.g. for Token Macro resolution in Mail Ext Plugin. Such properties are not supposed to be resolved when importing configurations, but the JCasC plugin has no way to determine which variables should be resolved when reading the configurations.
In some cases non-admin users can contribute to JCasC exports if they have some permissions
(e.g. agent/view configuration or credentials management),
and they could potentially inject variable expressions in plain text fields like descriptions
and then see the resolved secrets in Jenkins Web UI if the Jenkins admin exports and imports the configuration without checking contents.
It led to a security vulnerability which was addressed in JCasC 1.25
(SECURITY-1446).
- When reading configuration YAMLs, JCasC plugin will try to resolve
all variables having the
${VARNAME}
format. - Starting from JCasC
1.25
, JCasC export escapes the internal variable expressions, e.g. as^${VARNAME}
, so newly exported and then imported configurations are are not subject for this risk - For previously exported configurations, Jenkins admins are expected to manually
resolve the issues by putting the escape symbol
^
in front of variables which should not be resolved
Prerequisites: HashiCorp Vault plugin v2.4.0+
- The environment variable
CASC_VAULT_PW
must be present, if token is not used and appRole/Secret is not used. (Vault password.) - The environment variable
CASC_VAULT_USER
must be present, if token is not used and appRole/Secret is not used. (Vault username.) - The environment variable
CASC_VAULT_APPROLE
must be present, if token is not used and U/P not used. (Vault AppRole ID.) - The environment variable
CASC_VAULT_APPROLE_SECRET
must be present, it token is not used and U/P not used. (Vault AppRole Secret ID.) - The environment variable
CASC_VAULT_TOKEN
must be present, if U/P is not used. (Vault token.) - The environment variable
CASC_VAULT_PATHS
must be present. (Comma separated vault key paths. For example,secret/jenkins,secret/admin
.) - The environment variable
CASC_VAULT_URL
must be present. (Vault url, including port number.) - The environment variable
CASC_VAULT_MOUNT
is optional. (Vault auth mount. For example,ldap
or another username & password authentication type, defaults touserpass
.) - The environment variable
CASC_VAULT_NAMESPACE
is optional. If used, sets the Vault namespace for Enterprise Vaults. - The environment variable
CASC_VAULT_FILE
is optional, provides a way for the other variables to be read from a file instead of environment variables. - The environment variable
CASC_VAULT_ENGINE_VERSION
is optional. If unset, your vault path is assumed to be using kv version 2. If your vault path uses engine version 1, set this variable to1
. - The issued token should have read access to vault path
auth/token/lookup-self
in order to determine its expiration time. JCasC will re-issue a token if its expiration is reached (except forCASC_VAULT_TOKEN
).
If the environment variables CASC_VAULT_URL
and CASC_VAULT_PATHS
are present, JCasC will try to gather initial secrets from Vault. However for it to work properly there is a need for authentication by either the combination of CASC_VAULT_USER
and CASC_VAULT_PW
, a CASC_VAULT_TOKEN
, or the combination of CASC_VAULT_APPROLE
and CASC_VAULT_APPROLE_SECRET
. The authenticated user must have at least read access.
You can also provide a CASC_VAULT_FILE
environment variable where you load the secrets from a file.
File should be in a Java Properties format
CASC_VAULT_PW=PASSWORD
CASC_VAULT_USER=USER
CASC_VAULT_TOKEN=TOKEN
CASC_VAULT_PATHS=secret/jenkins/master,secret/admin
CASC_VAULT_URL=https://vault.dot.com
CASC_VAULT_MOUNT=ldap
A good use for CASC_VAULT_FILE
would be together with docker secrets.
version: "3.6"
services:
jenkins:
environment:
CASC_VAULT_FILE: /run/secrets/jcasc_vault
restart: always
build: .
image: jenkins.master:v1.0
ports:
- 8080:8080
- 50000:50000
volumes:
- jenkins-home:/var/jenkins_home
secrets:
- jcasc_vault
volumes:
jenkins-home:
secrets:
jcasc_vault:
file: ./secrets/jcasc_vault
TODO: Provide a Dockerfile to generate documentation from specified jenkins-core release and plugins.
We don't support installing plugins with JCasC you need to use something else for this,
Dockers users can use:
https://github.com/jenkinsci/docker/#preinstalling-plugins
Kubernetes users:
https://github.com/helm/charts/tree/master/stable/jenkins
Most plugins should be supported out-of-the-box, or maybe require some minimal changes. See this dashboard for known compatibility issues.
You have the following option to trigger a configuration reload:
-
via the user interface:
Manage Jenkins -> Configuration -> Reload existing configuration
-
via http POST to
JENKINS_URL/configuration-as-code/reload
Note: this needs to include a valid CRUMB and authentication information e.g. username + token of a user with admin permissions. Since Jenkins 2.96 CRUMB is not needed for API tokens. -
via Jenkins CLI
-
via http POST to
JENKINS_URL/reload-configuration-as-code
It's disabled by default and secured via a token configured as system propertycasc.reload.token
. Setting the system property enables this functionality and the requests need to include the token as query parameter namedcasc-reload-token
, i.e.JENKINS_URL/reload-configuration-as-code/?casc-reload-token=32424324rdsadsa
.curl -X POST "JENKINS_URL:8080/reload-configuration-as-code/?casc-reload-token=32424324rdsadsa"
- configuration-as-code-groovy-plugin Allows to specify groovy code that should run on during configuration.
- configuration-as-code-secret-ssm-plugin Allows to resolve secrets from AWS' SSM secrets
- hashicorp-vault-plugin Allows to resolve secrets from Hashicorp vault
As configuration as code is demonstrated to be a highly requested topic in Jenkins community, we have published JEP 201 as proposal to make this a standard component of the Jenkins project. The proposal was accepted. ๐