Maintenance policy management

Written by

Yandex Cloud

Updated at July 8, 2024

Create a VM with a configured maintenance policy
Check the maintenance event processing
Connect to the VM via SSH
Create a script to track VM maintenance events
Simulate the occurrence of a VM maintenance event
Change the VM maintenance policy type

To enable and configure a VM maintenance policy, complete the following steps:

Create a VM with a configured maintenance policy

CLI

Terraform

Create a VM with the maintenance policies:

FOLDER_ID=$(yc config get folder-id)

yc compute instance create --name mnt-vm1 --hostname mnt-vm1\
  --folder-id $FOLDER_ID \
  --zone ru-central1-a \
  --create-boot-disk image-folder-id=standard-images,image-family=ubuntu-2204-lts \
  --cores=2 --memory=4G --core-fraction=100 \
  --network-interface subnet-name=default-ru-central1-a,ipv4-address=auto,nat-ip-version=ipv4 \
  --ssh-key ~/.ssh/id_ed25519.pub \
  --maintenance-policy restart \
  --maintenance-grace-period 1m

Create the mnt-vm.tf Terraform manifest:

terraform {
  required_providers {
    yandex = {
      source  = "yandex-cloud/yandex"
      version = "~> 0.105.0"
    }
  }
}

variable "folder_id" {
  type = string
}

data "yandex_compute_image" "vm_image" {
  family = "ubuntu-2204-lts"
}

data "yandex_vpc_subnet" "vm_subnet" {
  folder_id = var.folder_id
  name      = "default-ru-central1-a"
}

resource "yandex_compute_instance" "vm_instance" {
  name                     = "mnt-vm1"
  folder_id                = var.folder_id
  hostname                 = "mnt-vm1"
  zone                     = "ru-central1-a"
  maintenance_policy       = "restart" # restart| migrate | unspecified
  maintenance_grace_period = "1m"

  resources {
    cores  = 2
    memory = 4
  }

  boot_disk {
    initialize_params {
      image_id = data.yandex_compute_image.vm_image.id
    }
  }

  network_interface {
    subnet_id = data.yandex_vpc_subnet.vm_subnet.id
    nat       = true
  }

  metadata = {
    ssh-keys = "ubuntu:${file("~/.ssh/id_ed25519.pub")}"
  }
}

Apply the Terraform manifest:

export YC_TOKEN=$(yc iam create-token)
export TF_VAR_folder_id=$(yc config get folder-id)

terraform init
terraform apply

Check the maintenance event processing

You can use the CLI to check the configuration of the VM maintenance policies after it has been created. Run this command:

yc compute instance get --name=mnt-vm1 --format=json | grep maintenance

Expected result:

  "maintenance_policy": "RESTART",
  "maintenance_grace_period": "60s"

Connect to the VM via SSH

Get the VM IP address and save it to a variable, then connect to the VM via SSH with your username:

VM_IP=$(yc compute instance get --name=mnt-vm1 --format=json | jq -r '.network_interfaces[0].primary_v4_address.one_to_one_nat.address')

ssh <username>@$VM_IP

Create a script to track VM maintenance events

Create a file named mnt-pol.sh and paste the following code to it:

#!/bin/bash

while true
do
  echo -n `date`" : "
  curl -s -H Metadata-Flavor:Google http://metadata.google.internal/computeMetadata/v1/instance/maintenance-event
  echo
  sleep 1
done

Run the script:

chmod u+x mnt-pol.sh
./mnt-pol.sh

Simulate the occurrence of a VM maintenance event

Simulate the occurrence of a maintenance event using the CLI. Run this command:

yc compute instance simulate-maintenance-event --name=mnt-vm1

Make sure the event is displayed in the terminal:

yc-user@mnt-vm1:~$ ./mnt-pol.sh
Tue Jan 16 14:14:40 UTC 2024 : NONE
Tue Jan 16 14:14:41 UTC 2024 : NONE
...
Tue Jan 16 14:23:38 UTC 2024 : NONE
Tue Jan 16 14:23:39 UTC 2024 : TERMINATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:23:40 UTC 2024 : TERMINATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:23:41 UTC 2024 : TERMINATE_ON_HOST_MAINTENANCE
...
Tue Jan 16 14:24:48 UTC 2024 : TERMINATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:24:49 UTC 2024 : NONE

Change the VM maintenance policy type

You can change the VM maintenance policy type by specifying a new value for the --maintenance-policy parameter with the following command:

yc compute instance update --name=mnt-vm1 --maintenance-policy=migrate

Simulate the occurrence of a maintenance event using the CLI:

yc compute instance simulate-maintenance-event --name=mnt-vm1

Run the script again and make sure the policy has changed:

yc-user@mnt-vm1:~$ ./mnt-pol.sh
Tue Jan 16 14:32:09 UTC 2024 : NONE
Tue Jan 16 14:32:10 UTC 2024 : NONE
...
Tue Jan 16 14:32:23 UTC 2024 : MIGRATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:32:24 UTC 2024 : MIGRATE_ON_HOST_MAINTENANCE
...
Tue Jan 16 14:33:23 UTC 2024 : MIGRATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:33:24 UTC 2024 : MIGRATE_ON_HOST_MAINTENANCE
Tue Jan 16 14:33:25 UTC 2024 : NONE

Maintenance policy management

Create a VM with a configured maintenance policyCreate a VM with a configured maintenance policy

Check the maintenance event processingCheck the maintenance event processing

Connect to the VM via SSHConnect to the VM via SSH

Create a script to track VM maintenance eventsCreate a script to track VM maintenance events

Simulate the occurrence of a VM maintenance eventSimulate the occurrence of a VM maintenance event

Change the VM maintenance policy typeChange the VM maintenance policy type