SNO on SPOT

Single Node OpenShift on AWS Spot for < $100/mon

Prerequisites:

• AWS command line
• AWS account login
• OpenShift pull secret
• OpenShift command line and installer
• ec2-spot-converter script

Generate DynamoDB Table

This step needs to be performed once in each region and account that you will be provisioning instances. It serves as a temporal tracking table for the tool.

export AWS_PROFILE=default
export AWS_DEFAULT_REGION=ap-southeast-1
ec2-spot-converter --generate-dynamodb-table

Install and Adjust the SNO instance

This portion performs a SNO install and then moves it to the public subnets. It will remove the unneeded portions of the networking infrastructure.

1. Create Openshift SNO AWS Config

   mkdir -p cluster
   # vi install-config.yaml
   # update: pullSecret, sshKey, region, type, rootVolume: size, metadata: name, baseDomain
   cp install-config.yaml cluster/

2. Install OpenShift

   export AWS_PROFILE=rhpds
   export AWS_DEFAULT_REGION=ap-southeast-1
   openshift-install create cluster --dir=cluster

3. Export Env.Vars

   export KUBECONFIG=<path to your>/cluster/auth/kubeconfig 
   export CLUSTER_NAME=my-cluster
   export BASE_DOMAIN=sandbox.acme.com

4. Adjust AWS Objects

   Dry run (no changes, just perform lookups). Do this first to check output, as the script may over select.

   ./adjust-single-node.sh

   DoIt !

   ./adjust-single-node.sh -d

5. Check

   It may take a couple of minutes for SNO to settle down (authentication, ingress operators become available). You should now be able to login to your cluster OK. Check oc get co to make sure cluster operators are healthy. Check the router ELB has the instance associated (this will be temporary until you run the fix instance id script).

Convert SNO to SPOT pricing

This portion does the actual conversion to persistent spot instance pricing.

export INSTANCE_ID=$(aws ec2 describe-instances \
--query "Reservations[].Instances[].InstanceId" \
--filters "Name=tag-value,Values=$CLUSTER_NAME-*-master-0" "Name=instance-state-name,Values=running" \
--output text)

ec2-spot-converter --stop-instance --instance-id $INSTANCE_ID

There are several other options for the tool not used here but which could be invoked:

• max spot price
• change instance type
• delete the AMI when it completes
• change the encryption key for the root volume
• convert from spot back to on-demand

Documentation of the settings and how to use them are on the ec2-spot-converter tool's homepage.

Fix the internal node instance references

After converting to spot, there are a few references to the old instance ID in the cluster which must be remedied so the operators function correctly for the life of the cluster.

1. Export Env.Vars

   export AWS_PROFILE=default
   export AWS_DEFAULT_REGION=ap-southeast-1
   export BASE_DOMAIN=sandbox.acme.com #replace by a real domain and make sure you have a Hosted Zone for it at Route 53!
   export CLUSTER_NAME=my-cluster
   export KUBECONFIG=<path to your $RUNDIR>/cluster/auth/kubeconfig 

2. Fix internal node instance references

   Dry run (no changes, just perform lookups). Do this first to check.

   ./fix-instance-id.sh

   DoIt !

   ./fix-instance-id.sh -d

3. Check

   It may take a couple of minutes for SNO to settle after restarting (authentication, ingress operators become available). You should now be able to login to your cluster OK. Check oc get co to make sure cluster operators are healthy. Check the router ELB has the instance associated OK, this should be done automatically now by the node.

Delete SNO instance

1. If you no longer need your instance, to remove all related aws objects just run inside your $RUNDIR.

   openshift-install destroy cluster --dir=cluster

💥💥 Try the all-in-one installation 💥💥

1. Try the all-in-one invocation.

   export AWS_PROFILE=default
   export AWS_DEFAULT_REGION=ap-southeast-1
   export CLUSTER_NAME=my-cluster
   export BASE_DOMAIN=sandbox.acme.com #replace by a real domain and make sure you have a Hosted Zone for it at Route 53!
   export INSTANCE_TYPE=m6a.2xlarge
   export PULL_SECRET=$(cat ~/tmp/pull-secret)
   export SSH_KEY=$(cat ~/.ssh/id_rsa.pub)
   
   mkdir my-run && cd my-run
   curl -Ls https://raw.githubusercontent.com/eformat/sno-for-100/main/sno-for-100.sh | bash -s -- -d

Day#2 Enhancements

You may want to try out these common day.2 enhancements for your SNO on SPOT instance.

• Extra Storage
• Performance Enhancements
• Cluster Route Certificates with Let's Encrypt