Installing Rancher in a Single Docker Container on Ubuntu 20.04

This is MUCH easier than my last couple of posts because this just takes one step after you configure your OS. Rancher is a cloud native (runs on its own K8s/K3s cluster) K8s manager and container orchestration platform. It is a competitor to Red Hat OpenShift and VMWare Tanzu.

This solution is for a DEV/practice environment. 

I've uploaded the script to configure Ubuntu as a gist to Github. So all you need to do is start with a working install of Ubuntu 20.04 desktop (my test systems have been configured with 16 cores and 64GB RAM). Your user must have sudo access (you'll be prompted for the password as the scripts run) and you can run this script:

configureUbuntu.sh

Now run this command:

docker run -d --restart=unless-stopped \

  -p 80:80 -p 443:443 \

  --privileged \

  rancher/rancher:latest

Now open your browser to http://localhost and follow the directions. It will instruct you how to get the password, then prompt you to change the password, and you're good to go. You have a local Rancher K3s cluster running in a docker container. From the UI you can probe your cluster configuration, install new applications, etc. One application of interest is:

Monitoring - This is similar to (though not exactly) the kube-prometheus-stack, with Prometheus, Grafana, and several Grafana dashboards configured.

To access the cluster from the CLI, you first need to get the container-id of your rancher container with:

docker ps

Then run:

docker exec -it container-id /bin/bash

At this point you have a root shell with access to the kubectl command.

Another application that will probably interest you is Elasticsearch. Be prepared for a LOT of failure if you try to install this one. I simply could not get it to install, and I could not determine why it failed. I couldn't find any useful logs describing where it was getting hung up. If you can figure it out, please let me know. I will keep on trying.

Update 3/16/2023: I was able to get Elasticsearch installed, and I can verify via curl to port 9200 that it's running, but that's it. I can't get any logs sent to it because the Logging app won't let me configure anything. And while I can install Kibana, I cannot figure out how to access the UI once it's installed. I've tried quite a few different things, but it's not working.

To get Elasticsearch installed, you need to perform some additional steps:

Create a directory like /home/mypv inside the Rancher docker container.

Set the owner of that directory to the user "rancher"

create a PersistentVolume in the Rancher UI to be a HostPath that points to /home/mypv with a size of 30Gi (to match the defaults for the Elasticsearch install)

In the Elasticsearch yaml, change the values of these two keys as listed here:

replicas: 1

minimumMasterNodes: 1

But, like I said, you won't be able to actually do anything with it at this point.