Category: OpenShift

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Containers Github OpenShift Red Hat

OCP & Private Github Repos

So you have your OpenShift 4.x cluster deployed, now it’s time to deploy some code. In this post I will describe how to get started deploying your code from private repos hosted on GitHub.

First let’s create a specific ssh key just for this use. If you have a linux system you can do this by running the following command.

ssh-keygen -t rsa -b 4096 -C "mike@example.com"

This will generate your private and public key you will use for the project. Next we need to add the newly created public key to deploy keys section for the repo we want to deploy from at Github; you can do that by following the tutorial here.

Now that you have done this we need to add our private key to our OpenShift project to be able to run the code on our cluster. From your project click the Add option from the left hand menu. Then we want to choose From Git.

Next we will input our git project ssh url into the Git Repo URL field, followed by clicking the Show Advanced Git Options. Here we will need to add our private ssh key we generated earlier by clicking Select Secret Name followed by Create New Secret.

This will bring us to the screen where we want to add our private key to OpenShift as a new secret. We can do this by choosing SSH Key from the Authentication Type drop down menu and naming our new secret and pasting our ssh private key into the field and clicking create.

Select your builder image, name, and any advanced options and click Create. Your project should be deployed after a bit of time.

-Mike

Categories
OpenShift Red Hat

Adjusting OCP worker node resources

Let’s say that you deployed your OpenShift cluster with all the defaults using the installer provisioned infrastructure method. Not only that but you’ve got your some workloads already deployed but you want to adjust all the resources available to the underlying worker node VMs. How do you do that? I will detail those steps in this article!

You will need to figure out what the minimal worker node count that is needed to run your workloads. In this example we will use one but this will work if you have more. You could simply increase the replica count after adjusting the machineset instead.

First we will need to get the name of the machineset we will be altering.

oc get machinesets -n openshift-machine-api

Then we will scale the worker nodes to one replica in this example using the machineset name from the above command (ocp4-tkqrm-worker).

oc scale --replicas=1 ocp4-tkqrm-worker -n openshift-machine-api

Now let’s get the name of the worker node(s) that is/are left. We will use this later to delete those machines after we have edited our resources and scaled our cluster back up. Make sure to take the name of them down or run in a separate terminal to reference later when we remove them.

oc get nodes

Now let’s edit our machineset resources to whatever we like using the following command.

oc edit machineset ocp4-tkqrm-worker -n openshift-machine-api

Once you have edited the machineset we need to scale it back up. This will deploy all new worker nodes with the newly adjusted resource requirements. Note left over worker node resources will not change and this is why we need to delete them later in the tutorial.

oc scale --replicas=3 ocp4-tkqrm-worker -n openshift-machine-api

Once the new machines are deployed and operational displaying the ready status using the oc get nodes command; we can delete the older worker nodes.

oc delete machine ocp4-tkqrm-worker-dzrvt -n openshift-machine-api

Note the above command will take a while to run while it drains the node of any pods that are running. Once the command completes, your cluster should have all new worker nodes with the newly specified resources!

-Mike

Categories
OpenShift Red Hat

Manually scaling an OCP IPI Cluster

In this article I will discuss how to manually scale an OpenShift IPI up or down depending on your needs. It is very easy to do with the oc binary via the command line. Whether you need to scale up your worker nodes to support more workloads or scale down to save on costs it can be done with one command.

First we need to login to our cluster via the oc command line utility.

oc login https://api.ocp4.example.com:6443

Next we need to get the name of the machineset for our cluster that we will be scaling.

oc get machinesets -n openshift-machine-api

This will return the name of our machinset as seen in the screenshot below.

Then we can run the following command to scale the cluster up or down adjusting the replicas=X portion of the command. Where X is the number of replicas to scale up or down to. You also need to adjust the machineset name to the one from the above command. 

oc scale --replicas=4 ocp4-tkqrm-worker -n openshift-machine-api

You can use the oc get command from above to watch for the additional nodes to be added or removed depending on what you choice to do this will take some time. Do note that you can NOT scale to zero worker nodes without moving the router pods.

-Mike

Categories
OpenShift Red Hat Virtualization

Custom OpenShift VMWare IPI Deployments

In the past few posts I have written how to do some basic setup tasks once you have a OpenShift deployment up and running. I figured I should backpedal a little here and discuss how to do a custom OpenShift deployment on VMWare using the IPI deployment method.

To start when you do a basic deployment of OpenShift with the openshift-install binary you get a basic cluster with 3x supervisor nodes and 3x worker nodes. While this is great for folks interested in just getting to know OpenShift, if you are deploying production workloads you may want to increase the supervisor/worker node counts.

By default the 3x worker nodes are deployed 2x CPU counts with a single core on each socket, 8GB of RAM, and 120GB hard drive. Well if you wanted to increase these default values, you are in luck; I will detail that process below!

First we need to create a directory to hold our custom install-config.yml and installation files for our cluster.

mkdir install-dir

Next we want to create our custom install-config.yml used to spin up our custom OpenShift cluster deployment. We can do this using the openshift-install cli tool by running the following command and filling in all the necessary information about our VMWare cluster and our OpenShift cluster we are deploying.

openshift-install create install-config --dir=./install-dir

Next we need to edit the newly created install-config.yml in the installation directory we created. It will look like the snippet below in the screenshot. Notice the platform variable is set to {}, we will need to edit this to have the proper amount of resources we want to give our OpenShift cluster VMs.

To do this all we need to do is remove the {} and add some new variables to our yaml file to specify the platform (vsphere in this example), cpus, coresPerSocket, memoryMB, and diskSizeGB. Below you will see an example of deploying supervisor and worker nodes with 3 replicas each with 4 CPUs, 2 cores per socket, 16GB of RAM, and 120GB hard drives.

After you have edited the install-config.yml just go ahead and write the file and now we can run the create cluster command to deploy our custom configured OpenShift install.

openshift-install create cluster --dir=./install-dir

Enjoy your newly customized OpenShift cluster!

-Mike

Categories
OpenShift Red Hat

Cluster admin access in OCP 4.x via CLI

In the last blog post we went over how to add users to cluster-admin role in your OpenShift 4.x cluster. In this post I will detail how to make a user a cluster admin using the CLI which I have found to be the quickest method of doing so.

First we will have to log in to the cli using the kubeadmin user to provide cluster-admin level access to the accounts we created before.

oc login https://api.ocp4.example.com:6443

Now that we are logged in as kubeadmin, let’s grant cluster-admin access to a user account.

oc adm policy add-cluster-role-to-user cluster-admin <username>

Once you have done this for all users who need cluster-admin level access let’s login using that user using the oc login command from above. Let’s check that we have cluster-admin access by running the following command.

oc get nodes

This should return the names of the supervisor and worker nodes if successful. Next we will want to remove the temporary cluster-admin kubeadmin. We can do this by running the command below.

oc delete secrets kubeadmin -n kube-system

Congrats you have now setup your OCP users and given them cluster-admin access while removing the default account.

-Mike

Categories
OpenShift Red Hat

Cluster admin access in OCP 4.x via WebUI

In the last blog post we went over how to add users to your OpenShift 4.x cluster using basic htpasswd authentication. In this post I will detail how to make a user a cluster admin so you can remove the default kubeadmin account.

First we will have to log in to the webui using the kubeadmin user to provide cluster-admin level access to the accounts we created before. After you have logged in expand the left hand menu that says User Management followed by clicking Role Bindings and finally Create Binding.

On the next screen we will setup our Role Binding. First we want to specify that this is a Cluster-wide Role Binding by checking the radio button for Binding Type. Next we need to give it a Name; this can be whatever you like. In this example I use new-admin-0. The Role Name we will select is cluster-admin. Finally we will put the username to give cluster-admin access to in the Subject Name box leaving the User radio button selected as seen below.

If all went well we should be able to log out of the webui as kubeadmin and log in as our user we just gave cluster-admin access to. We should have full access to all namespaces/projects like the kubeadmin user did. If so let’s continue on and delete the temporary kubeadmin account.

We can do this by clicking Workloads in the left hand menu followed by Secrets. We want to make sure our Project is set to kube-system else you will not see the kubeadmin secret.

Once you have located the kubeadmin secret you can click the 3 vertical dot menu on the right hand side for that secret and select Delete Secret.

Congrats you have successfully added your HTPasswd users to the cluster-admin role and removed the temporary cluster-admin account kubeadmin!

-Mike

Categories
OpenShift Red Hat

HTPasswd Auth in OpenShift 4.x

In this post I will describe how to add basic HTPasswd authentication users to an OpenShift 4.x cluster.

First you will want to create a htpasswd file with all the users you want for your cluster. I will not cover that in this post but you should be able to find tutorials all over the web for doing such. The key here is to make sure you have the file in hand ready to upload to your OCP 4.x cluster.

Log in to your OCP cluster via the web interface using the kubeadmin user that is provided by default after the cluster installation. From here you should have a message at the top saying you’ve logged in using a temporary administrator like the one below.

Click the link in that message to take you to the OAuth details page for the cluster where you will have the option to add Identity Providers.

Click on the Add drop down followed by HTPasswd which will take you to the Add Identity Provider: HTPasswd page.

From here you will browse for your .htpasswd file and click the Add button. This will create the custom resource and secret needed to do authentication via HTPasswd.

In the next post I will discuss how to adding the cluster-admin role to these users.

-Mike

Categories
Containers OpenShift Red Hat

PostgreSQL on OpenShift 4.x

I had a little side project that used a PostgreSQL database for the backend and was initially deployed on a virtual machine. Well we wanted to modernize the deployment and move the database to OpenShift 4.6 using containers. In this post I will detail a quick and dirty way to take a PostgreSQL backup file and restore on top of OCP.

We will do the first half of this tutorial using the web ui and wrap it up with the cli. From the developer view we will click add from the left menu and select database.

Now we will look for PostgreSQL in the developer catalog and select it. Note we want to use the option without ephemeral in it’s name.

Next we are prompted with our template options before deployment. Go ahead and fill out this information according to your needs and click create. Do note the default as of 11/9/2020 deploys PostgreSQL 10.8 but we can change the version of the PostgreSQL image used to latest to get version 12.

Finally we are going to switch to the cli and import or backup that we made using pgdump. Once you are logged into oc you will want to run the following command. 

oc get pods

Ignore the pod ending in deploy with status completed, what we want is the running container that ends in 5 random characters. Now let’s setup a port-forward to our local machine with the pgdump file in hand.

oc port-forward my-database-54dfv 5432:5432

Where the my-database-54dfv is the name we obtained from the oc get pods command we ran earlier and the ports are local:remote so if you want to change the local port you may if you are doing this from the actual VM already running PostgreSQL.

Once we have the port-forward setup for our local machine now we just need to import our database backup with the following.

psql database-name username --host 127.0.0.1 < /path/to/pgdump-file

Congrats you should now have your database restored and running in a container that can be accessed by the service name you provided during creation.

-Mike

Categories
Containers OpenShift RHEL

OpenShift Origin 3.11 on RHEL 7

OpenShift Origin (OKD) 3.11 on a single node while using RHEL 7 can be a bit different than the CentOS 7 install. In this article I will cover those instructions. We will assume you have installed the latest version of RHEL 7 on your node that you will be deploying on.

From there you will want to log in and update the system after enabling the repos we need.

sudo subscription-manager repos --disable "*"

sudo subscription-manager repos --enable=rhel-7-server-rpms --enable=rhel-7-server-extras-rpms

sudo yum update -y

Next we will install the dependencies we need to continue followed by a reboot.

sudo yum install -y python3-pip python-devel git && sudo yum group install -y "Development Tools" && sudo reboot

Now that we have our dependencies installed and our system up to date we will want to clone the openshift-ansible install from github.

git clone https://github.com/openshift/openshift-ansible
cd openshift-ansible
git checkout release-3.11

Now we will install the python dependencies using pip we installed earlier.

sudo pip3 install -r requirements.txt

Finally we run the two playbooks needed to deploy the standalone 3.11 version of OpenShift on RHEL 7.

sudo /usr/local/bin/ansible-playbook -i inventory/hosts.localhost playbooks/prerequisites.yml
sudo /usr/local/bin/ansible-playbook -i inventory/hosts.localhost playbooks/deploy_cluster.yml

Enjoy your OpenShift Origin 3.11 test environment on RHEL 7!

Categories
CentOS Containers Linux OpenShift

OpenShift Origin 3.11 on CentOS 7

I had a friend who was having some issues with installing OpenShift Origin (OKD) 3.11 on a single node so I took to documenting my steps taken for my test deployment. We will assume you have installed the latest version of CentOS on your node that you will be deploying on.

From there you will want to log in and update the system.

sudo yum update -y

Next we will install the dependencies we need to continue followed by a reboot.

sudo yum install -y epel-release && sudo yum install -y python-pip python-devel git && sudo yum group install -y "Development Tools" && sudo reboot

Now that we have our dependencies installed and our system up to date we will want to clone the openshift-ansible install from github.

git clone https://github.com/openshift/openshift-ansible
cd openshift-ansible
git checkout release-3.11

Now we will install the python dependencies using pip we installed earlier.

sudo pip install -r requirements.txt

Finally we run the two playbooks needed to deploy the standalone 3.11 version of OpenShift on CentOS 7.

sudo ansible-playbook -i inventory/hosts.localhost playbooks/prerequisites.yml
sudo ansible-playbook -i inventory/hosts.localhost playbooks/deploy_cluster.yml

Enjoy your OpenShift Origin 3.11 test environment!