515 lines
18 KiB
Markdown
515 lines
18 KiB
Markdown
---
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author: Achilleas Pipinellis
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author_gitlab: axil
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level: intermediary
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article_type: tutorial
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date: 2016-06-28
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---
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# Getting started with OpenShift Origin 3 and GitLab
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## Introduction
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[OpenShift Origin][openshift] is an open source container application
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platform created by [RedHat], based on [kubernetes] and [Docker]. That means
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you can host your own PaaS for free and almost with no hassle.
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In this tutorial, we will see how to deploy GitLab in OpenShift using GitLab's
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official Docker image while getting familiar with the web interface and CLI
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tools that will help us achieve our goal.
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For a video demonstration on installing GitLab on Openshift, check the article [In 13 minutes from Kubernetes to a complete application development tool](https://about.gitlab.com/2016/11/14/idea-to-production/).
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---
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## Prerequisites
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OpenShift 3 is not yet deployed on RedHat's offered Online platform ([openshift.com]),
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so in order to test it, we will use an [all-in-one Virtualbox image][vm] that is
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offered by the OpenShift developers and managed by Vagrant. If you haven't done
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already, go ahead and install the following components as they are essential to
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test OpenShift easily:
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- [VirtualBox]
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- [Vagrant]
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- [OpenShift Client][oc] (`oc` for short)
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It is also important to mention that for the purposes of this tutorial, the
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latest Origin release is used:
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- **oc** `v1.3.0` (must be [installed][oc-gh] locally on your computer)
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- **openshift** `v1.3.0` (is pre-installed in the [VM image][vm-new])
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- **kubernetes** `v1.3.0` (is pre-installed in the [VM image][vm-new])
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>**Note:**
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If you intend to deploy GitLab on a production OpenShift cluster, there are some
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limitations to bare in mind. Read on the [limitations](#current-limitations)
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section for more information and follow the linked links for the relevant
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discussions.
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Now that you have all batteries, let's see how easy it is to test OpenShift
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on your computer.
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## Getting familiar with OpenShift Origin
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The environment we are about to use is based on CentOS 7 which comes with all
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the tools needed pre-installed: Docker, kubernetes, OpenShift, etcd.
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### Test OpenShift using Vagrant
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As of this writing, the all-in-one VM is at version 1.3, and that's
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what we will use in this tutorial.
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In short:
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1. Open a terminal and in a new directory run:
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```sh
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vagrant init openshift/origin-all-in-one
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```
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1. This will generate a Vagrantfile based on the all-in-one VM image
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1. In the same directory where you generated the Vagrantfile
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enter:
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```sh
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vagrant up
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```
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This will download the VirtualBox image and fire up the VM with some preconfigured
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values as you can see in the Vagrantfile. As you may have noticed, you need
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plenty of RAM (5GB in our example), so make sure you have enough.
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Now that OpenShift is setup, let's see how the web console looks like.
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### Explore the OpenShift web console
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Once Vagrant finishes its thing with the VM, you will be presented with a
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message which has some important information. One of them is the IP address
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of the deployed OpenShift platform and in particular <https://10.2.2.2:8443/console/>.
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Open this link with your browser and accept the self-signed certificate in
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order to proceed.
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Let's login as admin with username/password `admin/admin`. This is what the
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landing page looks like:
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You can see that a number of [projects] are already created for testing purposes.
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If you head over the `openshift-infra` project, a number of services with their
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respective pods are there to explore.
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We are not going to explore the whole interface, but if you want to learn about
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the key concepts of OpenShift, read the [core concepts reference][core] in the
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official documentation.
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### Explore the OpenShift CLI
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OpenShift Client (`oc`), is a powerful CLI tool that talks to the OpenShift API
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and performs pretty much everything you can do from the web UI and much more.
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Assuming you have [installed][oc] it, let's explore some of its main
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functionalities.
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Let's first see the version of `oc`:
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```sh
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$ oc version
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oc v1.3.0
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kubernetes v1.3.0+52492b4
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```
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With `oc help` you can see the top level arguments you can run with `oc` and
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interact with your cluster, kubernetes, run applications, create projects and
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much more.
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Let's login to the all-in-one VM and see how to achieve the same results like
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when we visited the web console earlier. The username/password for the
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administrator user is `admin/admin`. There is also a test user with username/
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password `user/user`, with limited access. Let's login as admin for the moment:
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```sh
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$ oc login https://10.2.2.2:8443
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Authentication required for https://10.2.2.2:8443 (openshift)
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Username: admin
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Password:
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Login successful.
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You have access to the following projects and can switch between them with 'oc project <projectname>':
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* cockpit
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* default (current)
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* delete
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* openshift
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* openshift-infra
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* sample
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Using project "default".
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```
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Switch to the `openshift-infra` project with:
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```sh
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oc project openshift-infra
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```
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And finally, see its status:
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```sh
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oc status
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```
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The last command should spit a bunch of information about the statuses of the
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pods and the services, which if you look closely is what we encountered in the
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second image when we explored the web console.
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You can always read more about `oc` in the [OpenShift CLI documentation][oc].
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### Troubleshooting the all-in-one VM
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Using the all-in-one VM gives you the ability to test OpenShift whenever you
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want. That means you get to play with it, shutdown the VM, and pick up where
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you left off.
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Sometimes though, you may encounter some issues, like OpenShift not running
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when booting up the VM. The web UI may not responding or you may see issues
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when trying to login with `oc`, like:
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```
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The connection to the server 10.2.2.2:8443 was refused - did you specify the right host or port?
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```
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In that case, the OpenShift service might not be running, so in order to fix it:
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1. SSH into the VM by going to the directory where the Vagrantfile is and then
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run:
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```sh
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vagrant ssh
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```
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1. Run `systemctl` and verify by the output that the `openshift` service is not
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running (it will be in red color). If that's the case start the service with:
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```sh
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sudo systemctl start openshift
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```
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1. Verify the service is up with:
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```sh
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systemctl status openshift -l
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```
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Now you will be able to login using `oc` (like we did before) and visit the web
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console.
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## Deploy GitLab
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Now that you got a taste of what OpenShift looks like, let's deploy GitLab!
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### Create a new project
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First, we will create a new project to host our application. You can do this
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either by running the CLI client:
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```bash
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$ oc new-project gitlab
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```
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or by using the web interface:
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If you used the command line, `oc` automatically uses the new project and you
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can see its status with:
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```sh
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$ oc status
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In project gitlab on server https://10.2.2.2:8443
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You have no services, deployment configs, or build configs.
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Run 'oc new-app' to create an application.
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```
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If you visit the web console, you can now see `gitlab` listed in the projects list.
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The next step is to import the OpenShift template for GitLab.
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### Import the template
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The [template][templates] is basically a JSON file which describes a set of
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related object definitions to be created together, as well as a set of
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parameters for those objects.
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The template for GitLab resides in the Omnibus GitLab repository under the
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docker directory. Let's download it locally with `wget`:
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```bash
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wget https://gitlab.com/gitlab-org/omnibus-gitlab/raw/master/docker/openshift-template.json
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```
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And then let's import it in OpenShift:
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```bash
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oc create -f openshift-template.json -n openshift
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```
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>**Note:**
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The `-n openshift` namespace flag is a trick to make the template available to all
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projects. If you recall from when we created the `gitlab` project, `oc` switched
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to it automatically, and that can be verified by the `oc status` command. If
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you omit the namespace flag, the application will be available only to the
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current project, in our case `gitlab`. The `openshift` namespace is a global
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one that the administrators should use if they want the application to be
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available to all users.
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We are now ready to finally deploy GitLab!
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### Create a new application
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The next step is to use the template we previously imported. Head over to the
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`gitlab` project and hit the **Add to Project** button.
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This will bring you to the catalog where you can find all the pre-defined
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applications ready to deploy with the click of a button. Search for `gitlab`
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and you will see the previously imported template:
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Select it, and in the following screen you will be presented with the predefined
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values used with the GitLab template:
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Notice at the top that there are three resources to be created with this
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template:
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- `gitlab-ce`
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- `gitlab-ce-redis`
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- `gitlab-ce-postgresql`
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While PostgreSQL and Redis are bundled in Omnibus GitLab, the template is using
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separate images as you can see from [this line][line] in the template.
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The predefined values have been calculated for the purposes of testing out
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GitLab in the all-in-one VM. You don't need to change anything here, hit
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**Create** to start the deployment.
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If you are deploying to production you will want to change the **GitLab instance
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hostname** and use greater values for the volume sizes. If you don't provide a
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password for PostgreSQL, it will be created automatically.
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>**Note:**
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The `gitlab.apps.10.2.2.2.xip.io` hostname that is used by default will
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resolve to the host with IP `10.2.2.2` which is the IP our VM uses. It is a
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trick to have distinct FQDNs pointing to services that are on our local network.
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Read more on how this works in <http://xip.io>.
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Now that we configured this, let's see how to manage and scale GitLab.
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## Manage and scale GitLab
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Setting up GitLab for the first time might take a while depending on your
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internet connection and the resources you have attached to the all-in-one VM.
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GitLab's docker image is quite big (~500MB), so you'll have to wait until
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it's downloaded and configured before you use it.
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### Watch while GitLab gets deployed
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Navigate to the `gitlab` project at **Overview**. You can notice that the
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deployment is in progress by the orange color. The Docker images are being
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downloaded and soon they will be up and running.
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Switch to the **Browse > Pods** and you will eventually see all 3 pods in a
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running status. Remember the 3 resources that were to be created when we first
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created the GitLab app? This is where you can see them in action.
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You can see GitLab being reconfigured by taking look at the logs in realtime.
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Click on `gitlab-ce-2-j7ioe` (your ID will be different) and go to the **Logs**
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tab.
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At a point you should see a _**gitlab Reconfigured!**_ message in the logs.
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Navigate back to the **Overview** and hopefully all pods will be up and running.
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Congratulations! You can now navigate to your new shinny GitLab instance by
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visiting <http://gitlab.apps.10.2.2.2.xip.io> where you will be asked to
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change the root user password. Login using `root` as username and providing the
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password you just set, and start using GitLab!
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### Scale GitLab with the push of a button
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If you reach to a point where your GitLab instance could benefit from a boost
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of resources, you'd be happy to know that you can scale up with the push of a
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button.
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In the **Overview** page just click the up arrow button in the pod where
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GitLab is. The change is instant and you can see the number of [replicas] now
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running scaled to 2.
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Upping the GitLab pods is actually like adding new application servers to your
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cluster. You can see how that would work if you didn't use GitLab with
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OpenShift by following the [HA documentation][ha] for the application servers.
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Bare in mind that you may need more resources (CPU, RAM, disk space) when you
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scale up. If a pod is in pending state for too long, you can navigate to
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**Browse > Events** and see the reason and message of the state.
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### Scale GitLab using the `oc` CLI
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Using `oc` is super easy to scale up the replicas of a pod. You may want to
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skim through the [basic CLI operations][basic-cli] to get a taste how the CLI
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commands are used. Pay extra attention to the object types as we will use some
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of them and their abbreviated versions below.
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In order to scale up, we need to find out the name of the replication controller.
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Let's see how to do that using the following steps.
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1. Make sure you are in the `gitlab` project:
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```sh
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oc project gitlab
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```
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1. See what services are used for this project:
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```sh
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oc get svc
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```
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The output will be similar to:
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```
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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gitlab-ce 172.30.243.177 <none> 22/TCP,80/TCP 5d
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gitlab-ce-postgresql 172.30.116.75 <none> 5432/TCP 5d
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gitlab-ce-redis 172.30.105.88 <none> 6379/TCP 5d
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```
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1. We need to see the replication controllers of the `gitlab-ce` service.
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Get a detailed view of the current ones:
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```sh
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oc describe rc gitlab-ce
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```
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This will return a large detailed list of the current replication controllers.
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Search for the name of the GitLab controller, usually `gitlab-ce-1` or if
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that failed at some point and you spawned another one, it will be named
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`gitlab-ce-2`.
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1. Scale GitLab using the previous information:
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```sh
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oc scale --replicas=2 replicationcontrollers gitlab-ce-2
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```
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1. Get the new replicas number to make sure scaling worked:
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```sh
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oc get rc gitlab-ce-2
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```
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which will return something like:
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```
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NAME DESIRED CURRENT AGE
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gitlab-ce-2 2 2 5d
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```
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And that's it! We successfully scaled the replicas to 2 using the CLI.
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As always, you can find the name of the controller using the web console. Just
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click on the service you are interested in and you will see the details in the
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right sidebar.
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### Autoscaling GitLab
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In case you were wondering whether there is an option to autoscale a pod based
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on the resources of your server, the answer is yes, of course there is.
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We will not expand on this matter, but feel free to read the documentation on
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OpenShift's website about [autoscaling].
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## Current limitations
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As stated in the [all-in-one VM][vm] page:
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> By default, OpenShift will not allow a container to run as root or even a
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non-random container assigned userid. Most Docker images in the Dockerhub do not
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follow this best practice and instead run as root.
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The all-in-one VM we are using has this security turned off so it will not
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bother us. In any case, it is something to keep in mind when deploying GitLab
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on a production cluster.
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In order to deploy GitLab on a production cluster, you will need to assign the
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GitLab service account to the `anyuid` Security Context.
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1. Edit the Security Context:
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```sh
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oc edit scc anyuid
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```
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1. Add `system:serviceaccount:<project>:gitlab-ce-user` to the `users` section.
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If you changed the Application Name from the default the user will
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will be `<app-name>-user` instead of `gitlab-ce-user`
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1. Save and exit the editor
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## Conclusion
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By now, you should have an understanding of the basic OpenShift Origin concepts
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and a sense of how things work using the web console or the CLI.
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GitLab was hard to install in previous versions of OpenShift,
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but now that belongs to the past. Upload a template, create a project, add an
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application and you are done. You are ready to login to your new GitLab instance.
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And remember that in this tutorial we just scratched the surface of what Origin
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is capable of. As always, you can refer to the detailed
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[documentation][openshift-docs] to learn more about deploying your own OpenShift
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PaaS and managing your applications with the ease of containers.
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[RedHat]: https://www.redhat.com/en "RedHat website"
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[openshift]: https://www.openshift.org "OpenShift Origin website"
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[vm]: https://www.openshift.org/vm/ "OpenShift All-in-one VM"
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[vm-new]: https://atlas.hashicorp.com/openshift/boxes/origin-all-in-one "Official OpenShift Vagrant box on Atlas"
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[template]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/docker/openshift-template.json "OpenShift template for GitLab"
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[openshift.com]: https://openshift.com "OpenShift Online"
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[kubernetes]: http://kubernetes.io/ "Kubernetes website"
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[Docker]: https://www.docker.com "Docker website"
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[oc]: https://docs.openshift.org/latest/cli_reference/get_started_cli.html "Documentation - oc CLI documentation"
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[VirtualBox]: https://www.virtualbox.org/wiki/Downloads "VirtualBox downloads"
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[Vagrant]: https://www.vagrantup.com/downloads.html "Vagrant downloads"
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[projects]: https://docs.openshift.org/latest/dev_guide/projects.html "Documentation - Projects overview"
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[core]: https://docs.openshift.org/latest/architecture/core_concepts/index.html "Documentation - Core concepts of OpenShift Origin"
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[templates]: https://docs.openshift.org/latest/architecture/core_concepts/templates.html "Documentation - OpenShift templates"
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[old-post]: https://blog.openshift.com/deploy-gitlab-openshift/ "Old post - Deploy GitLab on OpenShift"
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[line]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/658c065c8d022ce858dd63eaeeadb0b2ddc8deea/docker/openshift-template.json#L239 "GitLab - OpenShift template"
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[oc-gh]: https://github.com/openshift/origin/releases/tag/v1.3.0 "Openshift 1.3.0 release on GitHub"
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[ha]: ../../administration/high_availability/gitlab.html "Documentation - GitLab High Availability"
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[replicas]: https://docs.openshift.org/latest/architecture/core_concepts/deployments.html#replication-controllers "Documentation - Replication controller"
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[autoscaling]: https://docs.openshift.org/latest/dev_guide/pod_autoscaling.html "Documentation - Autoscale"
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[basic-cli]: https://docs.openshift.org/latest/cli_reference/basic_cli_operations.html "Documentation - Basic CLI operations"
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[openshift-docs]: https://docs.openshift.org "OpenShift documentation"
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