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What Is This

This repository contains almost everything you need to have a production-quality deployment of Pulp on Kubernetes. You provide a running k8s cluster plus shared storage.

TLS with client certificate authentication is used among the services. A self-signed CA and all required certificates are created and distributed automatically.

This is highly experimental and not yet officially supported. If there is interest, and if others can help get these materials tested and improved, it could become a fully supported and recommended deployment model by the Pulp Project.

Getting Started

To start quickly with a demo-quality single-node kubernetes cluster, try minikube. When you have a running cluster, proceed.

Storage

Create storage for pulp, qpidd, and mongodb. Before creating these resources, adjust each PersistentVolume to match the storage you can provide. The defaults only work on a single-node deployment (such as minikube).

kubectl create -f resources/vlp.yaml
kubectl create -f resources/vlq.yaml
kubectl create -f resources/vlm.yaml

Secrets

server.conf

Edit secrets/full-server.conf to your liking. Defaults will work, but consider such settings as the initial admin password. For settings that are already populated with non-default values, those values are likely important to integration with other k8s resources. It's wise to understand the current value before changing it.

Certificates

This script creates a self-signed CA, and all of the certificates needed by the various pulp services.

./make-certs.sh

If you prefer to provide your own certificates, pause here and replace what was generated. Most of the output is in the certs directory, but qpidd requires an NSS database found in the qpidd directory.

RSA Key Pair

Just run the script to generate the pair.

./pulp-gen-key-pair

Commit

Done! Now run the provided script to "commit" the secrets into k8s.

./commit.sh

At any time you can stop services, run delete.sh to remove the secrets from k8s, modify values as you like, and then re-commit with commit.sh. Then start everything back up.

Supporting Services

MongoDB and Qpid are ready to be started. They must remain singletons, so do not scale beyond 1 pod each.

kubectl create -f resources/mongo.yaml
kubectl create -f resources/qpid.yaml

Setup

Almost done. We need two setup steps.

The first time you deploy, run the setup pod to establish the correct filesystem layout on your shared storage.

kubectl create -f resources/setup.yaml

Watch for the setup pod to finish by running this command:

kubectl get pods -a

Every time you deploy a new version of Pulp, including the first deployment, run pulp-manage-db. Make sure that no Pulp services are running.

kubectl create -f resources/manage.yaml

As above, watch for completion with this command:

kubectl get pods -a

Start Pulp

This script is a shortcut for creating the Pulp resources. Before creating them, feel free to adjust the number of replicas of each Deployment resource. For anything more serious than a demo, I would start with 4-8 workers, and 2 of each other Pulp service.

./up.sh

Access Pulp

This deployment uses the most recent Fedora release in the container images. For now, it is up to you to run your own machine with the same version of Fedora, or otherwise install pulp-admin of the same version that matches the images.

Since I use Fedora on my laptop anyway, this document will proceed with that.

Start by installing pulp-admin.

Create the file ~/.pulp/admin.conf with these contents, adjusted for wherever you have this git repository checked out.

[server]
host = pulpapi
port = 30443
ca_path = /home/mhrivnak/git/pulp-k8s/secrets/certs/ca.crt

Find the external IP address for one or more nodes in your cluster. If using minikube:

minikube ip

Edit your /etc/hosts file so the name pulpapi resolved to those addresses. Or use a DNS service if you have one handy.

sudo echo 192.168.42.149 pulpapi >> /etc/hosts

Cross your fingers, and then clumsily type:

pulp-admin status

Assuming the status looks good, you are now free to log in and use Pulp as normal.

Scaling

Need more workers? No problem.

kubectl scale --replicas=16 deployment/worker

Finished a batch of work and ready to scale back? Just as easy.

kubectl scale --replicas=4 deployment/worker

For maximum fun, I like to run this in another terminal while scaling workers:

watch -n 1 pulp-admin status

Limitations

Load Balancing

Kubernetes does not yet have a great story around load balancing or highly available access to services that want to terminate their own TLS. Pulp is currently suited to running TCP from the client all the way to the httpd process for that very purpose.

The new Ingress resource type appears to be targeting layer 7, so it is not useful in this case.

For now we are using the NodePort feature of the Service resource, which limits us by default to a range of ports above 30000.

Please suggest ideas if you have them.

On-Demand Support Not Deployed

This does not yet include support for Alternate Download Policies. I think it would be straight-forward to add. We just need to:

  • install the streamer on the base image
  • create a new image that runs squid
  • create Deployment resources for both the streamer and squid

REST API Coupled With Content Serving

For simplicity, I made one httpd pod template that does everything. This includes serving the REST API and serving published content. Those are very different roles with different characteristics, and httpd already runs them in different processes.

It would be better to make a separate pod template for each. That may require substantial modification of Pulp's default httpd configuration, which is the main reason I avoided it so far.