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diff --git a/doc/articles/openshift_and_gitlab/index.md b/doc/articles/openshift_and_gitlab/index.md new file mode 100644 index 00000000000..96a83089670 --- /dev/null +++ b/doc/articles/openshift_and_gitlab/index.md @@ -0,0 +1,534 @@ +# Getting started with OpenShift Origin 3 and GitLab + +> **Article [Type](../../development/writing_documentation.html#types-of-technical-articles):** tutorial || +> **Level:** intermediary || +> **Author:** [Achilleas Pipinellis](https://gitlab.com/axil) || +> **Publication date:** 2016/06/28 + + +## Introduction + +[OpenShift Origin][openshift] is an open source container application +platform created by [RedHat], based on [kubernetes] and [Docker]. That means +you can host your own PaaS for free and almost with no hassle. + +In this tutorial, we will see how to deploy GitLab in OpenShift using GitLab's +official Docker image while getting familiar with the web interface and CLI +tools that will help us achieve our goal. + +--- + +### What's on this page? +{: .no_toc} + +- TOC +{:toc} + +--- + +## Prerequisites + +OpenShift 3 is not yet deployed on RedHat's offered Online platform ([openshift.com]), +so in order to test it, we will use an [all-in-one Virtualbox image][vm] that is +offered by the OpenShift developers and managed by Vagrant. If you haven't done +already, go ahead and install the following components as they are essential to +test OpenShift easily: + +- [VirtualBox] +- [Vagrant] +- [OpenShift Client][oc] (`oc` for short) + +It is also important to mention that for the purposes of this tutorial, the +latest Origin release is used: + +- **oc** `v1.3.0` (must be [installed][oc-gh] locally on your computer) +- **openshift** `v1.3.0` (is pre-installed in the [VM image][vm-new]) +- **kubernetes** `v1.3.0` (is pre-installed in the [VM image][vm-new]) + +<div class="panel panel-info"> +**Note** +{: .panel-heading} +<div class="panel-body"> +If you intend to deploy GitLab on a production OpenShift cluster, there are some +limitations to bare in mind. Read on the [limitations](#current-limitations) +section for more information and follow the linked links for the relevant +discussions. +</div> +</div> + +Now that you have all batteries, let's see how easy it is to test OpenShift +on your computer. + +## Getting familiar with OpenShift Origin + +The environment we are about to use is based on CentOS 7 which comes with all +the tools needed pre-installed: Docker, kubernetes, OpenShift, etcd. + +### Test OpenShift using Vagrant + +As of this writing, the all-in-one VM is at version 1.3, and that's +what we will use in this tutorial. + +In short: + +1. Open a terminal and in a new directory run: + ```sh + vagrant init openshift/origin-all-in-one + ``` +1. This will generate a Vagrantfile based on the all-in-one VM image +1. In the same directory where you generated the Vagrantfile + enter: + + ```sh + vagrant up + ``` + +This will download the VirtualBox image and fire up the VM with some preconfigured +values as you can see in the Vagrantfile. As you may have noticed, you need +plenty of RAM (5GB in our example), so make sure you have enough. + +Now that OpenShift is setup, let's see how the web console looks like. + +### Explore the OpenShift web console + +Once Vagrant finishes its thing with the VM, you will be presented with a +message which has some important information. One of them is the IP address +of the deployed OpenShift platform and in particular <https://10.2.2.2:8443/console/>. +Open this link with your browser and accept the self-signed certificate in +order to proceed. + +Let's login as admin with username/password `admin/admin`. This is what the +landing page looks like: + + + +You can see that a number of [projects] are already created for testing purposes. + +If you head over the `openshift-infra` project, a number of services with their +respective pods are there to explore. + + + +We are not going to explore the whole interface, but if you want to learn about +the key concepts of OpenShift, read the [core concepts reference][core] in the +official documentation. + +### Explore the OpenShift CLI + +OpenShift Client (`oc`), is a powerful CLI tool that talks to the OpenShift API +and performs pretty much everything you can do from the web UI and much more. + +Assuming you have [installed][oc] it, let's explore some of its main +functionalities. + +Let's first see the version of `oc`: + +```sh +$ oc version + +oc v1.3.0 +kubernetes v1.3.0+52492b4 +``` + +With `oc help` you can see the top level arguments you can run with `oc` and +interact with your cluster, kubernetes, run applications, create projects and +much more. + +Let's login to the all-in-one VM and see how to achieve the same results like +when we visited the web console earlier. The username/password for the +administrator user is `admin/admin`. There is also a test user with username/ +password `user/user`, with limited access. Let's login as admin for the moment: + +```sh +$ oc login https://10.2.2.2:8443 + +Authentication required for https://10.2.2.2:8443 (openshift) +Username: admin +Password: +Login successful. + +You have access to the following projects and can switch between them with 'oc project <projectname>': + + * cockpit + * default (current) + * delete + * openshift + * openshift-infra + * sample + +Using project "default". +``` + +Switch to the `openshift-infra` project with: + +```sh +oc project openshift-infra +``` + +And finally, see its status: + +```sh +oc status +``` + +The last command should spit a bunch of information about the statuses of the +pods and the services, which if you look closely is what we encountered in the +second image when we explored the web console. + +You can always read more about `oc` in the [OpenShift CLI documentation][oc]. + +### Troubleshooting the all-in-one VM + +Using the all-in-one VM gives you the ability to test OpenShift whenever you +want. That means you get to play with it, shutdown the VM, and pick up where +you left off. + +Sometimes though, you may encounter some issues, like OpenShift not running +when booting up the VM. The web UI may not responding or you may see issues +when trying to login with `oc`, like: + +``` +The connection to the server 10.2.2.2:8443 was refused - did you specify the right host or port? +``` + +In that case, the OpenShift service might not be running, so in order to fix it: + +1. SSH into the VM by going to the directory where the Vagrantfile is and then + run: + + ```sh + vagrant ssh + ``` + +1. Run `systemctl` and verify by the output that the `openshift` service is not + running (it will be in red color). If that's the case start the service with: + + ```sh + sudo systemctl start openshift + ``` + +1. Verify the service is up with: + + ```sh + systemctl status openshift -l + ``` + +Now you will be able to login using `oc` (like we did before) and visit the web +console. + +## Deploy GitLab + +Now that you got a taste of what OpenShift looks like, let's deploy GitLab! + +### Create a new project + +First, we will create a new project to host our application. You can do this +either by running the CLI client: + +```bash +$ oc new-project gitlab +``` + +or by using the web interface: + + + +If you used the command line, `oc` automatically uses the new project and you +can see its status with: + +```sh +$ oc status + +In project gitlab on server https://10.2.2.2:8443 + +You have no services, deployment configs, or build configs. +Run 'oc new-app' to create an application. +``` + +If you visit the web console, you can now see `gitlab` listed in the projects list. + +The next step is to import the OpenShift template for GitLab. + +### Import the template + +The [template][templates] is basically a JSON file which describes a set of +related object definitions to be created together, as well as a set of +parameters for those objects. + +The template for GitLab resides in the Omnibus GitLab repository under the +docker directory. Let's download it locally with `wget`: + +```bash +wget https://gitlab.com/gitlab-org/omnibus-gitlab/raw/master/docker/openshift-template.json +``` + +And then let's import it in OpenShift: + +```bash +oc create -f openshift-template.json -n openshift +``` + +<div class="panel panel-info"> +**Note** +{: .panel-heading} +<div class="panel-body"> +The `-n openshift` namespace flag is a trick to make the template available to all +projects. If you recall from when we created the `gitlab` project, `oc` switched +to it automatically, and that can be verified by the `oc status` command. If +you omit the namespace flag, the application will be available only to the +current project, in our case `gitlab`. The `openshift` namespace is a global +one that the administrators should use if they want the application to be +available to all users. +</div> +</div> + +We are now ready to finally deploy GitLab! + +### Create a new application + +The next step is to use the template we previously imported. Head over to the +`gitlab` project and hit the **Add to Project** button. + + + +This will bring you to the catalog where you can find all the pre-defined +applications ready to deploy with the click of a button. Search for `gitlab` +and you will see the previously imported template: + + + +Select it, and in the following screen you will be presented with the predefined +values used with the GitLab template: + + + +Notice at the top that there are three resources to be created with this +template: + +- `gitlab-ce` +- `gitlab-ce-redis` +- `gitlab-ce-postgresql` + +While PostgreSQL and Redis are bundled in Omnibus GitLab, the template is using +separate images as you can see from [this line][line] in the template. + +The predefined values have been calculated for the purposes of testing out +GitLab in the all-in-one VM. You don't need to change anything here, hit +**Create** to start the deployment. + +If you are deploying to production you will want to change the **GitLab instance +hostname** and use greater values for the volume sizes. If you don't provide a +password for PostgreSQL, it will be created automatically. + +<div class="panel panel-info"> +**Note** +{: .panel-heading} +<div class="panel-body"> +The `gitlab.apps.10.2.2.2.xip.io` hostname that is used by default will +resolve to the host with IP `10.2.2.2` which is the IP our VM uses. It is a +trick to have distinct FQDNs pointing to services that are on our local network. +Read more on how this works in <http://xip.io>. +</div> +</div> + +Now that we configured this, let's see how to manage and scale GitLab. + +## Manage and scale GitLab + +Setting up GitLab for the first time might take a while depending on your +internet connection and the resources you have attached to the all-in-one VM. +GitLab's docker image is quite big (~500MB), so you'll have to wait until +it's downloaded and configured before you use it. + +### Watch while GitLab gets deployed + +Navigate to the `gitlab` project at **Overview**. You can notice that the +deployment is in progress by the orange color. The Docker images are being +downloaded and soon they will be up and running. + + + +Switch to the **Browse > Pods** and you will eventually see all 3 pods in a +running status. Remember the 3 resources that were to be created when we first +created the GitLab app? This is where you can see them in action. + + + +You can see GitLab being reconfigured by taking look at the logs in realtime. +Click on `gitlab-ce-2-j7ioe` (your ID will be different) and go to the **Logs** +tab. + + + +At a point you should see a _**gitlab Reconfigured!**_ message in the logs. +Navigate back to the **Overview** and hopefully all pods will be up and running. + + + +Congratulations! You can now navigate to your new shinny GitLab instance by +visiting <http://gitlab.apps.10.2.2.2.xip.io> where you will be asked to +change the root user password. Login using `root` as username and providing the +password you just set, and start using GitLab! + +### Scale GitLab with the push of a button + +If you reach to a point where your GitLab instance could benefit from a boost +of resources, you'd be happy to know that you can scale up with the push of a +button. + +In the **Overview** page just click the up arrow button in the pod where +GitLab is. The change is instant and you can see the number of [replicas] now +running scaled to 2. + + + +Upping the GitLab pods is actually like adding new application servers to your +cluster. You can see how that would work if you didn't use GitLab with +OpenShift by following the [HA documentation][ha] for the application servers. + +Bare in mind that you may need more resources (CPU, RAM, disk space) when you +scale up. If a pod is in pending state for too long, you can navigate to +**Browse > Events** and see the reason and message of the state. + + + +### Scale GitLab using the `oc` CLI + +Using `oc` is super easy to scale up the replicas of a pod. You may want to +skim through the [basic CLI operations][basic-cli] to get a taste how the CLI +commands are used. Pay extra attention to the object types as we will use some +of them and their abbreviated versions below. + +In order to scale up, we need to find out the name of the replication controller. +Let's see how to do that using the following steps. + +1. Make sure you are in the `gitlab` project: + + ```sh + oc project gitlab + ``` + +1. See what services are used for this project: + + ```sh + oc get svc + ``` + + The output will be similar to: + + ``` + NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE + gitlab-ce 172.30.243.177 <none> 22/TCP,80/TCP 5d + gitlab-ce-postgresql 172.30.116.75 <none> 5432/TCP 5d + gitlab-ce-redis 172.30.105.88 <none> 6379/TCP 5d + ``` + +1. We need to see the replication controllers of the `gitlab-ce` service. + Get a detailed view of the current ones: + + ```sh + oc describe rc gitlab-ce + ``` + + This will return a large detailed list of the current replication controllers. + Search for the name of the GitLab controller, usually `gitlab-ce-1` or if + that failed at some point and you spawned another one, it will be named + `gitlab-ce-2`. + +1. Scale GitLab using the previous information: + + ```sh + oc scale --replicas=2 replicationcontrollers gitlab-ce-2 + ``` + +1. Get the new replicas number to make sure scaling worked: + + ```sh + oc get rc gitlab-ce-2 + ``` + + which will return something like: + + ``` + NAME DESIRED CURRENT AGE + gitlab-ce-2 2 2 5d + ``` + +And that's it! We successfully scaled the replicas to 2 using the CLI. + +As always, you can find the name of the controller using the web console. Just +click on the service you are interested in and you will see the details in the +right sidebar. + + + +### Autoscaling GitLab + +In case you were wondering whether there is an option to autoscale a pod based +on the resources of your server, the answer is yes, of course there is. + +We will not expand on this matter, but feel free to read the documentation on +OpenShift's website about [autoscaling]. + +## Current limitations + +As stated in the [all-in-one VM][vm] page: + +> By default, OpenShift will not allow a container to run as root or even a +non-random container assigned userid. Most Docker images in the Dockerhub do not +follow this best practice and instead run as root. + +The all-in-one VM we are using has this security turned off so it will not +bother us. In any case, it is something to keep in mind when deploying GitLab +on a production cluster. + +In order to deploy GitLab on a production cluster, you will need to assign the +GitLab service account to the `anyuid` Security Context. + +1. Edit the Security Context: + ```sh + oc edit scc anyuid + ``` + +1. Add `system:serviceaccount:<project>:gitlab-ce-user` to the `users` section. + If you changed the Application Name from the default the user will + will be `<app-name>-user` instead of `gitlab-ce-user` + +1. Save and exit the editor + +## Conclusion + +By now, you should have an understanding of the basic OpenShift Origin concepts +and a sense of how things work using the web console or the CLI. + +GitLab was hard to install in previous versions of OpenShift, +but now that belongs to the past. Upload a template, create a project, add an +application and you are done. You are ready to login to your new GitLab instance. + +And remember that in this tutorial we just scratched the surface of what Origin +is capable of. As always, you can refer to the detailed +[documentation][openshift-docs] to learn more about deploying your own OpenShift +PaaS and managing your applications with the ease of containers. + +[RedHat]: https://www.redhat.com/en "RedHat website" +[openshift]: https://www.openshift.org "OpenShift Origin website" +[vm]: https://www.openshift.org/vm/ "OpenShift All-in-one VM" +[vm-new]: https://atlas.hashicorp.com/openshift/boxes/origin-all-in-one "Official OpenShift Vagrant box on Atlas" +[template]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/docker/openshift-template.json "OpenShift template for GitLab" +[openshift.com]: https://openshift.com "OpenShift Online" +[kubernetes]: http://kubernetes.io/ "Kubernetes website" +[Docker]: https://www.docker.com "Docker website" +[oc]: https://docs.openshift.org/latest/cli_reference/get_started_cli.html "Documentation - oc CLI documentation" +[VirtualBox]: https://www.virtualbox.org/wiki/Downloads "VirtualBox downloads" +[Vagrant]: https://www.vagrantup.com/downloads.html "Vagrant downloads" +[projects]: https://docs.openshift.org/latest/dev_guide/projects.html "Documentation - Projects overview" +[core]: https://docs.openshift.org/latest/architecture/core_concepts/index.html "Documentation - Core concepts of OpenShift Origin" +[templates]: https://docs.openshift.org/latest/architecture/core_concepts/templates.html "Documentation - OpenShift templates" +[old-post]: https://blog.openshift.com/deploy-gitlab-openshift/ "Old post - Deploy GitLab on OpenShift" +[line]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/658c065c8d022ce858dd63eaeeadb0b2ddc8deea/docker/openshift-template.json#L239 "GitLab - OpenShift template" +[oc-gh]: https://github.com/openshift/origin/releases/tag/v1.3.0 "Openshift 1.3.0 release on GitHub" +[ha]: http://docs.gitlab.com/ce/administration/high_availability/gitlab.html "Documentation - GitLab High Availability" +[replicas]: https://docs.openshift.org/latest/architecture/core_concepts/deployments.html#replication-controllers "Documentation - Replication controller" +[autoscaling]: https://docs.openshift.org/latest/dev_guide/pod_autoscaling.html "Documentation - Autoscale" +[basic-cli]: https://docs.openshift.org/latest/cli_reference/basic_cli_operations.html "Documentation - Basic CLI operations" +[openshift-docs]: https://docs.openshift.org "OpenShift documentation" |