Bash script for Instance Pool Lifecycle Management

This script will create a new image, a new instance configuration based on the new image and update the current instance pool with the new instance configuration.

After that, we can run recycle_instances.sh to recycle all the instances. See my previous post for details.

instance-config-ords-as-template.json

{
    "instanceType": "compute",
    "launchDetails": {
      "compartmentId": "{{compartmentId}}",
      "createVnicDetails": {
        "assignPublicIp": false
      },
      "metadata": {
        "ssh_authorized_keys": "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDuPoZBbXjC/5ojt+ECoIj5KGmLHWPPreWcjkp/1metOBgRv8f6W7w615+kRcrrdtyB5Tk6MzIs6CmF8RZ1BkkSankhHG62aKkqXn7T9VDenvEHaJpJqQRkhkYzJKyYqL+04O942gSgv8Kpw1IpFWvznfelf30xaxQzcLa0tMjYvOmqTmeAndEM3E1ZVMcEq3r3OlTTjCyfBPsdRPV2hFClvQziueRrUF61lhLotPUkCKxc6Iie+OpqW5hhU8vypFT0MAB6hoTH7EO7BGmQWInQlO3Pt4m7q9dNSee731TzRceDFa5cC/uigeAFgjEY8lwM5CFrcgMW3n3B3BpfumQv PC@PCLAPPY"
      },
        "shape": "VM.Standard.E3.Flex",
        "shapeConfig": {
          "memoryInGBs": 16.0,
          "ocpus": 1.0
        },
        "sourceDetails":   {
          "bootVolumeSizeInGBs": null,
          "imageId": "{{imageId}}",
          "sourceType": "image"
        }
    }
}

update_instance_pool_image_part2_template.txt

#!/usr/bin/bash

COMPARTMENT_OCID="{{compartmentId}}"
INSTANCE_POOL_OCID="{{instancepoolId}}"
INSTANCE_CONFIG_JSON="{{INSTANCE_CONFIG_JSON}}"
INSTANCE_CONFIG_NAME="{{INSTANCE_CONFIG_NAME}}"

INSTANCE_CONFIG_OCID=`oci compute-management instance-configuration create --compartment-id $COMPARTMENT_OCID --instance-details file://$INSTANCE_CONFIG_JSON --display-name $INSTANCE_CONFIG_NAME | jq -r '.data.id'`
sleep 30
oci compute-management instance-pool update --wait-for-state RUNNING --instance-pool-id $INSTANCE_POOL_OCID --instance-configuration-id $INSTANCE_CONFIG_OCID

update_instance_pool_image_part1.sh

#!/usr/bin/bash

COMPARTMENT_OCID="ocid1.compartment.oc1..aaaaaaaarocn3npultgruh5iwghhvor6s3kairokq4mil5bp52va6qkk7x6a"
INSTANCE_POOL_OCID="ocid1.instancepool.oc1.ca-toronto-1.aaaaaaaaswx6wld7z77u32shwivedvgn5usofurtjzfd3kdnfopbi56wqlfa"
INSTANCE_OCID="ocid1.instance.oc1.ca-toronto-1.an2g6ljrmpjzp2icj3zh7m5ndqp365ahhxv5j2b2u4t7omixuugdqwojymsq"

DATETIME=`date +"%Y-%m%d-%H%M"`
IMAGE_NAME="ords-as_"$DATETIME
INSTANCE_CONFIG_JSON="instance-config-ords-as_"$DATETIME".json"
INSTANCE_CONFIG_NAME="instance-config-ords-as_"$DATETIME
UPDATE_INSTANCE_POOL_SCRIPT="update_instance_pool_image_part2.sh"

sed "s/{{INSTANCE_CONFIG_JSON}}/$INSTANCE_CONFIG_JSON/g;s/{{INSTANCE_CONFIG_NAME}}/$INSTANCE_CONFIG_NAME/g;s/{{compartmentId}}/$COMPARTMENT_OCID/g;s/{{instancepoolId}}/$INSTANCE_POOL_OCID/g" update_instance_pool_image_part2_template.txt > $UPDATE_INSTANCE_POOL_SCRIPT
chmod 755 $UPDATE_INSTANCE_POOL_SCRIPT

IMAGE_OCID=`oci compute image create --compartment-id $COMPARTMENT_OCID --instance-id $INSTANCE_OCID --display-name $IMAGE_NAME | jq -r '.data.id'`

sed "s/{{imageId}}/$IMAGE_OCID/g;s/{{compartmentId}}/$COMPARTMENT_OCID/g" instance-config-ords-as-template.json > $INSTANCE_CONFIG_JSON

echo "Custom Image $IMAGE_NAME created. This instance will be taken offline for several minutes during the imaging process. Run update_pool_instance_image_part2.sh when instance come back online."

update_instance_pool_image_part2.sh

#!/usr/bin/bash

COMPARTMENT_OCID="ocid1.compartment.oc1..aaaaaaaarocn3npultgruh5iwghhvor6s3kairokq4mil5bp52va6qkk7x6a"
INSTANCE_POOL_OCID="ocid1.instancepool.oc1.ca-toronto-1.aaaaaaaaswx6wld7z77u32shwivedvgn5usofurtjzfd3kdnfopbi56wqlfa"
INSTANCE_CONFIG_JSON="instance-config-ords-as_2021-0308-0731.json"
INSTANCE_CONFIG_NAME="instance-config-ords-as_2021-0308-0731"

INSTANCE_CONFIG_OCID=`oci compute-management instance-configuration create  --compartment-id $COMPARTMENT_OCID --instance-details file://$INSTANCE_CONFIG_JSON --display-name $INSTANCE_CONFIG_NAME | jq -r '.data.id'`
sleep 30
oci compute-management instance-pool update --wait-for-state RUNNING --instance-pool-id $INSTANCE_POOL_OCID --instance-configuration-id $INSTANCE_CONFIG_OCID

Bash script to recycle all running instances in an instance pool

We have an instance pool, auto scaling with minimum 2 instances. After we update the instance configuration for the instance pool, we need to bring all running instances up to date.

The process is terminating one instance at a time, wait till the load balancer get back to "OK" and repeat. Eventually, we will terminated all instances with the old instance configuration with zero downtime.

recycle_instances.sh

#!/usr/bin/bash

COMPARTMENT_OCID="ocid1.compartment.oc1..aaaaaaaarocn3npultgruh5iwghhvor6s3kairokq4mil5bp52va6qkk7x6a"
LOAD_BALANCER_OCID="ocid1.loadbalancer.oc1.ca-toronto-1.aaaaaaaaxgcpd4izvacefithsabg3l4dhvl7y6gt2mcgitdlwt3ez45vzp5q"
INSTANCE_POOL_OCID="ocid1.instancepool.oc1.ca-toronto-1.aaaaaaaaswx6wld7z77u32shwivedvgn5usofurtjzfd3kdnfopbi56wqlfa"


# Wait till Load Balancer status is OK
lb_status_check () {
while [ "$LB_STATUS" != "OK" ]
do
  sleep 1m
  LB_STATUS=`oci lb load-balancer-health get --load-balancer-id $LOAD_BALANCER_OCID | jq -r '.data.status'`
  date
  echo "Load Balance Status: $LB_STATUS"
done
}

# Ensure Load Balancer is in OK status before we start
LB_STATUS=`oci lb load-balancer-health get --load-balancer-id $LOAD_BALANCER_OCID | jq -r '.data.status'`
lb_status_check

# Terminate all running instances in this instance pool
for INSTANCE_OCID in $(oci compute instance list --compartment-id $COMPARTMENT_OCID --lifecycle-state RUNNING | jq -r '.data[]| select(."freeform-tags"."oci:compute:instancepool" | contains("'$INSTANCE_POOL_OCID'"))? | .id') 
do
  date
  echo "Terminate instance OCID: ${INSTANCE_OCID}"
  oci compute instance terminate --force --instance-id ${INSTANCE_OCID}
  LB_STATUS="UNKNOWN"
  sleep 5m
  lb_status_check
done

date
echo "Recycle all running instances completed"