| # Gerrit slave on Kubernetes |
| |
| Gerrit is a web-based code review tool, which acts as a Git server. On large setups |
| Gerrit servers can see a sizable amount of traffic from git operations performed by |
| developers and build servers. The major part of requests are read-only requests |
| (e.g. by `git fetch` operations). To take some load of the Gerrit master server, |
| Gerrit slaves can be deployed to serve read-only requests. |
| |
| This helm chart provides a Gerrit slave setup that can be deployed on Kubernetes. |
| The Gerrit slave is capable of receiving replicated git repositories from a |
| Gerrit master. The slave can deploy its own database, that replicates the data |
| from the Gerrit master's database (Currently only MySQL databases are supported). |
| The Gerrit slave can then serve authenticated read-only requests. |
| |
| ## Prerequisites |
| |
| - Helm and Tiller (of course) |
| |
| (Check out [this guide](https://docs.helm.sh/using_helm/#quickstart-guide) |
| how to install and use helm.) |
| |
| - Access to a provisioner for persistent volumes with `Read Write Many (RWM)`- |
| capability. |
| |
| A list of applicaple volume types can be found |
| [here](https://kubernetes.io/docs/concepts/storage/persistent-volumes/#access-modes). |
| This project was developed using the |
| [NFS-server-provisioner helm chart](https://github.com/helm/charts/tree/master/stable/nfs-server-provisioner), |
| a NFS-provisioner deployed in the Kubernetes cluster itself. Refer to |
| [this guide](/helm-charts/gerrit-slave/docs/nfs-provisioner.md) of how to |
| deploy it in context of this project. |
| |
| - A domain name that is configured to point to the IP address of the node running |
| the Ingress controller on the kubernetes cluster (as described |
| [here](http://alesnosek.com/blog/2017/02/14/accessing-kubernetes-pods-from-outside-of-the-cluster/)). |
| |
| - (Optional: Required, if SSL is configured) |
| A [Java keystore](https://gerrit-review.googlesource.com/Documentation/config-gerrit.html#httpd.sslKeyStore) |
| to be used by Gerrit. |
| |
| ## Installing the Chart |
| |
| ***note |
| **ATTENTION:** The value for `gerritSlave.ingress.host` is required for rendering |
| the chart's templates. The nature of the value does not allow defaults. |
| Thus a custom `values.yaml`-file setting this value is required! |
| *** |
| |
| To install the chart with the release name `gerrit-slave`, execute: |
| |
| ```sh |
| cd $(git rev-parse --show-toplevel)/helm-charts |
| helm install ./gerrit-slave \ |
| --dep-up \ |
| -n gerrit-slave \ |
| -f <path-to-custom-values>.yaml |
| ``` |
| |
| The command deploys the Gerrit slave on the current Kubernetes cluster. The |
| [configuration section](#Configuration) lists the parameters that can be |
| configured during installation. |
| |
| ## Configuration |
| |
| The following sections list the configurable values in `values.yaml`. To configure |
| a Gerrit slave setup, make a copy of the `values.yaml`-file and change the |
| parameters as needed. The configuration can be applied by installing the chart as |
| described [above](#Installing-the-chart). |
| |
| In addition, single options can be set without creating a custom `values.yaml`: |
| |
| ```sh |
| cd $(git rev-parse --show-toplevel)/helm-charts |
| helm install ./gerrit-slave \ |
| --dep-up \ |
| -n gerrit-slave \ |
| --set=gitRepositoryStorage.size=100Gi,gitBackend.replicas=2 |
| ``` |
| |
| ### Container images |
| |
| | Parameter | Description | Default | |
| |--------------------------------------------|------------------------------------------------------|----------------------------------------------------------------------| |
| | `images.registry.name` | The image registry to pull the container images from | `` | |
| | `images.registry.ImagePullSecret.name` | Name of the ImagePullSecret | `image-pull-secret` (if empty no image pull secret will be deployed) | |
| | `images.registry.ImagePullSecret.create` | Whether to create an ImagePullSecret | `false` | |
| | `images.registry.ImagePullSecret.username` | The image registry username | `nil` | |
| | `images.registry.ImagePullSecret.password` | The image registry password | `nil` | |
| | `images.version` | The image version (image tag) to use | `latest` | |
| | `images.imagePullPolicy` | Image pull policy | `Always` | |
| |
| ### Storage classes |
| |
| For information of how a `StorageClass` is configured in Kubernetes, read the |
| [official Documentation](https://kubernetes.io/docs/concepts/storage/storage-classes/#introduction). |
| |
| | Parameter | Description | Default | |
| |----------------------------------------|-------------------------------------------------------------------|---------------------------------------------------| |
| | `storageClasses.default.name` | The name of the default StorageClass (RWO) | `default` | |
| | `storageClasses.default.create` | Whether to create the StorageClass | `false` | |
| | `storageClasses.default.provisioner` | Provisioner of the StorageClass | `kubernetes.io/aws-ebs` | |
| | `storageClasses.default.reclaimPolicy` | Whether to `Retain` or `Delete` volumes, when they become unbound | `Delete` | |
| | `storageClasses.default.parameters` | Parameters for the provisioner | `parameters.type: gp2`, `parameters.fsType: ext4` | |
| | `storageClasses.shared.name` | The name of the shared StorageClass (RWM) | `shared-storage` | |
| | `storageClasses.shared.create` | Whether to create the StorageClass | `false` | |
| | `storageClasses.shared.provisioner` | Provisioner of the StorageClass | `nfs` | |
| | `storageClasses.shared.reclaimPolicy` | Whether to `Retain` or `Delete` volumes, when they become unbound | `Delete` | |
| | `storageClasses.shared.parameters` | Parameters for the provisioner | `parameters.mountOptions: vers=4.1` | |
| |
| ### Storage for Git repositories |
| |
| | Parameter | Description | Default | |
| |-----------------------------|-------------------------------------------------|---------| |
| | `gitRepositoryStorage.size` | Size of the volume storing the Git repositories | `5Gi` | |
| |
| ### Apache-Git-HTTP-Backend (Git-Backend) |
| |
| | Parameter | Description | Default | |
| |------------------------------------------|-----------------------------------------------------------------------------|---------------------------------------------------------------------------| |
| | `gitBackend.image` | Image name of the Apache-git-http-backend container image | `k8s-gerrit/apache-git-http-backend` | |
| | `gitBackend.replicas` | Number of pod replicas to deploy | `1` | |
| | `gitBackend.resources` | Configure the amount of resources the pod requests/is allowed | `requests.cpu: 100m` | |
| | | | `requests.memory: 256Mi` | |
| | | | `limits.cpu: 100m` | |
| | | | `limits.memory: 256Mi` | |
| | `gitBackend.credentials.htpasswd` | `.htpasswd`-file containing username/password-credentials for accessing git | `git:$apr1$O/LbLKC7$Q60GWE7OcqSEMSfe/K8xU.` (user: git, password: secret) | |
| | `gitBackend.logging.persistence.enabled` | Whether to persist logs | `true` | |
| | `gitBackend.logging.persistence.size` | Storage size for persisted logs | `1Gi` | |
| | `gitBackend.service.type` | Which kind of Service to deploy | `LoadBalancer` | |
| | `gitBackend.service.http.enabled` | Whether to serve HTTP-requests (needed for Ingress) | `true` | |
| | `gitBackend.service.http.port` | Port over which to expose HTTP | `80` | |
| | `gitBackend.service.https.enabled` | Whether to serve HTTPS-requests | `false` | |
| | `gitBackend.service.https.port` | Port over which to expose HTTPS | `443` | |
| | `gitBackend.service.https.cert` | Public SSL server certificate | `-----BEGIN CERTIFICATE-----` | |
| | `gitBackend.service.https.key` | Private SSL server certificate | `-----BEGIN RSA PRIVATE KEY-----` | |
| | `gitBackend.ingress.enabled` | Whether to deploy an Ingress | `false` | |
| | `gitBackend.ingress.host` | Host name to use for the Ingress (required for Ingress) | `nil` | |
| | `gitBackend.ingress.alias` | Optional: ALias host name for the Ingress | `nil` | |
| | `gitBackend.ingress.tls.enabled` | Whether to enable TLS termination in the Ingress | `false` | |
| | `gitBackend.ingress.tls.cert` | Public SSL server certificate | `-----BEGIN CERTIFICATE-----` | |
| | `gitBackend.ingress.tls.key` | Private SSL server certificate | `-----BEGIN RSA PRIVATE KEY-----` | |
| |
| ***note |
| At least one endpoint (HTTP and/or HTTPS) has to be enabled in the service! |
| *** |
| |
| ### Git garbage collection |
| |
| | Parameter | Description | Default | |
| |-------------------------------------|------------------------------------------------------------------|--------------------------| |
| | `gitGC.image` | Image name of the Git-GC container image | `k8s-gerrit/git-gc` | |
| | `gitGC.schedule` | Cron-formatted schedule with which to run Git garbage collection | `0 6,18 * * *` | |
| | `gitGC.resources` | Configure the amount of resources the pod requests/is allowed | `requests.cpu: 100m` | |
| | | | `requests.memory: 256Mi` | |
| | | | `limits.cpu: 100m` | |
| | | | `limits.memory: 256Mi` | |
| | `gitGC.logging.persistence.enabled` | Whether to persist logs | `true` | |
| | `gitGC.logging.persistence.size` | Storage size for persisted logs | `1Gi` | |
| |
| ### Database |
| |
| The Gerrit slave requires a database containing the user data associated with the |
| replicated Git repositories, which is implemented as a database slave containing |
| the replicated data of the master database. |
| |
| ***note |
| Future implementations will provide the possibility to bring custom databases |
| from different providers, but so far the setup expects to setup its own MySQL |
| database. |
| *** |
| |
| | Parameter | Description | Default | |
| |--------------------------------|--------------------------------------------------------|---------| |
| | `database.provider` | Database type/provider to be used (Available: mysql) | `mysql` | |
| | `database.replication.enabled` | Whether to initialize replication from master database | `true` | |
| |
| The usual way to provide a database is meant to deploy it as a dependency of |
| this chart. Since the configuration of the database is different depending on |
| the database provider used, the configuration is described in separate documents: |
| |
| - [MySQL](/helm-charts/gerrit-slave/docs/mysql.md) |
| |
| ### Gerrit slave |
| |
| ***note |
| The way the Jetty servlet used by Gerrit works, the Gerrit slave component of the |
| gerrit-slave chart actually requires the URL to be known, when the chart is installed. |
| The suggested way to do that is to use the provided Ingress resource. This requires |
| that a URL is available and that the DNS is configured to point the URL to the |
| IP of the node the Ingress controller is running on! |
| *** |
| |
| ***note |
| Setting the canonical web URL in the gerrit.config to the host used for the Ingress |
| is mandatory, if access to the Gerrit slave is required! |
| *** |
| |
| | Parameter | Description | Default | |
| |----------------------------------------------|--------------------------------------------------------------------------------------------------------------------------|-----------------------------------| |
| | `gerritMaster.images.gerritInit` | Image name of the Gerrit init container image | `k8s-gerrit/gerrit-slave-init` | |
| | `gerritMaster.images.gerritSlave` | Image name of the Gerrit slave container image | `k8s-gerrit/gerrit-slave` | |
| | `gerritSlave.initializeTestSite.enabled` | Enable the initialization of a site. USE ONLY for testing, if you do not plan to replicate repositories or the database. | `true` | |
| | `gerritSlave.resources` | Configure the amount of resources the pod requests/is allowed | `requests.cpu: 1` | |
| | | | `requests.memory: 5Gi` | |
| | | | `limits.cpu: 1` | |
| | | | `limits.memory: 6Gi` | |
| | `gerritSlave.logging.persistence.enabled` | Whether to persist logs | `true` | |
| | `gerritSlave.logging.persistence.size` | Storage size for persisted logs | `1Gi` | |
| | `gerritSlave.h2Database.persistence.enabled` | Whether to persist h2 databases | `true` | |
| | `gerritSlave.h2Database.persistence.size` | Storage size for persisted h2 databases | `1Gi` | |
| | `gerritSlave.service.type` | Which kind of Service to deploy | `NodePort` | |
| | `gerritSlave.service.http.port` | Port over which to expose HTTP | `80` | |
| | `gerritSlave.ingress.host` | REQUIRED: Host name to use for the Ingress (required for Ingress) | `nil` | |
| | `gerritSlave.ingress.alias` | Optional: Alias host name for the Ingress | `nil` | |
| | `gerritSlave.ingress.tls.enabled` | Whether to enable TLS termination in the Ingress | `false` | |
| | `gerritSlave.ingress.tls.cert` | Public SSL server certificate | `-----BEGIN CERTIFICATE-----` | |
| | `gerritSlave.ingress.tls.key` | Private SSL server certificate | `-----BEGIN RSA PRIVATE KEY-----` | |
| | `gerritSlave.keystore` | base64-encoded Java keystore (`cat keystore.jks | base64`) to be used by Gerrit, when using SSL | `nil` | |
| | `gerritSlave.config.gerrit` | The contents of the gerrit.config | [see here](#Gerrit-config-files) | |
| | `gerritSlave.config.secure` | The contents of the secure.config | [see here](#Gerrit-config-files) | |
| |
| ### Gerrit config files |
| |
| The gerrit-slave chart provides a ConfigMap containing the `gerrit.config` and a |
| Secret containing the `secure.config` to configure the Gerrit installation in the |
| Gerrit slave component. The content of the `gerrit.config` and `secure.config` |
| can be set in the `values.yaml` under the keys `gerritSlave.config.gerrit` and |
| `gerritSlave.config.secure` respectively. All configuration options are described |
| in detail in the [official documentation of Gerrit](https://gerrit-review.googlesource.com/Documentation/config-gerrit.html). |
| Some options however have to be set in a specified way for the Gerrit slave to |
| work as intended: |
| |
| - `gerrit.basePath` |
| |
| Path to the directory containing the repositories. The chart mounts this |
| directory from a persistent volume to `/var/gerrit/git` in the container. For |
| Gerrit to find the correct directory, this has to be set to `git`. |
| |
| - `gerrit.serverId` |
| |
| In Gerrit-version higher than 2.14 Gerrit needs a server ID, which is used by |
| NoteDB. Gerrit would usually generate a random ID on startup, but since the |
| gerrit.config file is read only, when mounted as a ConfigMap this fails. |
| Thus the server ID has to be set manually! |
| |
| - `gerrit.canonicalWebUrl` |
| |
| The canonical web URL has to be set to the Ingress host. |
| |
| - `database.*` |
| |
| The default settings are configured to use the MySQL-database installed as a |
| dependency and if the chart is installed with the release name set to |
| `gerrit-slave`. Only change this, if you decide to use a different database or |
| changed the default settings for the mysql-chart. |
| |
| With newer versions of the MySQL-driver used by Gerrit, using SSL-encrypted |
| communication with the database is enforced by default. This can be deactivated |
| by setting the `useSSL=false`-option. To do that in Gerrit, the database-URL |
| has to be provided manually: |
| `url = jdbc:mysql://<db-host>:<db-port>/<db-name>?nullNamePatternMatchesAll=true&useSSL=false` |
| |
| - `httpd.listenURL` |
| |
| This has to be set to `proxy-http://*:8080/` or `proxy-https://*:8080`, |
| depending of TLS is enabled in the Ingress or not, otherwise the Jetty |
| servlet will run into an endless redirect loop. |
| |
| - `container.user` |
| |
| The technical user in the Gerrit slave container is called `gerrit`. Thus, this |
| value is required to be `gerrit`. |
| |
| - `container.slave` |
| |
| Since this chart is meant to install a Gerrit slave, this naturally has to be |
| `true`. |
| |
| - `container.javaHome` |
| |
| This has to be set to `/usr/lib/jvm/java-8-openjdk-amd64`, since this is |
| the path of the Java installation in the container. |
| |
| - `container.javaOptions` |
| |
| The maximum heap size has to be set. And its value has to be lower than the |
| memory resource limit set for the container (e.g. `-Xmx4g`). In your calculation |
| allow memory for other components running in the container. |
| |
| ## Upgrading the Chart |
| |
| To upgrade an existing installation of the gerrit-slave chart, e.g. to install |
| a newer chart version or to use an updated custom `values.yaml`-file, execute |
| the following command: |
| |
| ```sh |
| cd $(git rev-parse --show-toplevel)/helm-charts |
| helm upgrade <release-name> \ |
| -f <path-to-custom-values>.yaml \ |
| ./gerrit-slave |
| ``` |
| |
| ## Uninstalling the Chart |
| |
| To delete the chart from the cluster, use: |
| |
| ```sh |
| helm delete <release-name> \ |
| --purge |
| ``` |
