Rancher Suite K8S Adventure - Chapter 002 - Plan 1.0

Rancher Suite K8S Adventure - Chapter 002 - Plan 1.0

A travelogue of converting from OpenStack to Suse's Rancher Suite for K8S including RKE2, Harvester, kubectl, helm.

Starting conditions

I have two small OpenStack clusters running independently.  This way I can move everything from cluster one to cluster two, upgrade cluster one from version 'yoga' to version 'zed', then test and migrate everything to cluster one, then upgrade cluster two, etc.  It has proven to be operationally highly effective and efficient.  All I'm being wasteful about is running two copies of OpenStack Horizon which is pretty lightweight.  VMware had excellent incredibly reliable USB passthru and nothing else has that feature, so I have a couple tiny dedicated bare metal servers connected to various USB hardware (SDR devices, IoT microcontroller hardware, some home automation using ZWAVE, etc).  I have a TrueNAS NAS machine for slow bulk NFS and iSCSI storage that works pretty well.

First, set up a Rancher cluster.  Small Intel SBCs are now much cheaper and somewhat more readily available than slower lower capacity Raspberry Pi SBCs, which seems crazy to me, but I guess we live in interesting times.  My intent is to set up a three node RKE2 cluster and install Rancher on that microcluster.

Second, I have enough spare parts laying around to set up a small Harvester HCI cluster.  All I intend to buy is new, fresh, NVME for Longhorn cluster storage.  I can backup my Longhorn data to my existing TrueNAS server.  These ancient Intel NUCs are not high performance; but should be more than adequate for testing and experimentation.  I intend to apply "real world" container and VM workloads to this small cluster and document my experiences.

Third, I will migrate the workload off one of the two OpenStack clusters to the other OpenStack cluster and convert that hardware to a medium size Harvester cluster.  Given the experience in step two above, it should be easy to migrate the real world workload off the remaining OpenStack cluster to the new Harvester cluster.

Fourth, as the remaining OpenStack cluster should be empty now, I will convert that hardware into additional capacity for the now "large" sized Harvester cluster.

I would anticipate along the way I will have several systems to convert and document.  For example, currently the primary NTP servers for the LAN are the OpenStack servers.  I'm tentatively considering changing that to use the Rancher cluster hosts as the primary LAN NTP servers; everything on the LAN is configured with Ansible so this should be a half hour job?  Another example of a larger scale system is I do logging using an ElasticSearch cluster and MetricBeat/FileBeat and Kibana, etc, and I'm curious how well, or if, K8S integrates into an ElasticSearch logging infrastructure.  Speaking of everything on the LAN being configured with Ansible, I wonder how (or if?) I will be able to integrate the 'Rancher Suite' with Ansible.

Ending Conditions

One micro RKE2 cluster dedicated solely to running Rancher.  A small Harvester cluster mostly for experimentation although I may distribute some infrastructure workload on it for increased system reliability.  A 'large' Harvester cluster for real workload.

After you experience the operational flexibility and increased reliability of having multiple clusters, its hard to go back to having only one cluster.  Technically workload would easily fit on the 'large' Harvester cluster, but I will keep the small Harvester cluster around for experimentation purposes, etc.