Creating an instance group from Container Optimized Image

To run multiple instances of the service in Docker containers, you can create an instance group from a Container Optimized Image. In such groups, you can update Docker containers with VM metadata using the COI or Docker Compose specification.

By default, all operations in Instance Groups are performed on behalf of a service account. If you don't have a service account, create one.

To create an instance group built on a Container Optimized Image:

1. If you don't have the Yandex.Cloud command line interface yet, install and initialize it.

2. The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

3. View a description of the create instance group command in the CLI:

   $ yc compute instance-group create --help
   

4. Check whether there are networks in the folder:

   $ yc vpc network list
   

   If there aren't any, create one.

5. Create a YAML file with a name like specification.yaml.

6. Select the latest version of the Container Optimized Image from the public images.

   To get the ID of the latest version of the Container Optimized Image image, run the command:

   $ yc compute image get-latest-from-family container-optimized-image --folder-id standard-images
   id: <image ID>
   folder_id: standard-images
   ...
   

7. In the specification.yaml file you created, specify the following:

   • General information about the group:

     name: container-optimized-group
     service_account_id: aje3932acd8avp6edhbt
     description: "This instance group was created from YAML config."
     

     Keys:

     Key	Value
     name	A name for the instance group. The name must be unique within the folder. The name may contain lowercase Latin letters, numbers, and hyphens. The first character must be a letter. The last character can't be a hyphen. The maximum length of the name is 63 characters.
     service_account_id	ID of the service account.
     description	A description of the instance group.

   • Instance template:

     instance_template:
         platform_id: standard-v3
         resources_spec:
             memory: 2G
             cores: 2
         boot_disk_spec:
             mode: READ_WRITE
             disk_spec:
                 image_id: fd81a49qficqvt0dthu8
                 type_id: network-hdd
                 size: 32G
         network_interface_specs:
             - network_id: c64mknqgnd8avp6edhbt
               primary_v4_address_spec: {}
         metadata:
             docker-container-declaration: |-
                 spec:
                     containers:
                         - name: nginx
                           image: cr.yandex/mirror/nginx:1.17.4-alpine
                           securityContext:
                             privileged: false
                           tty: false
                           stdin: false
     

     The disk size is specified in bytes by default. You can specify a different unit of measurement using the applicable suffix.

     Name	Example of a YAML file entry:
     Kilobyte	1073741824k
     Megabyte	1048576m
     Gigabyte	1024g
     Terabyte	1t

     Keys:

     Key	Value
     platform_id	Platform ID.
     memory	Amount of memory (RAM).
     cores	Number of processor cores (vCPUs).
     mode	Disk access mode. - READ_ONLY: read-only access. - READ_WRITE: read/write access.
     image_id	ID of the public Container Optimized Image.
     type_id	Disk type.
     size	Disk size.
     network_id	The default-net ID.
     primary_v4_address_spec	IPv4 specification. Only IPv4 is currently available. You can allow public access to group instances by specifying the IP version for the public IP address. For more information, see Template description in a YAML file.
     metadata	Values to pass to the VM metadata.
     docker-container-declaration	The key in the VM metadata that is used with the COI specification of the Docker container. In the metadata, you can use the Docker Compose specification. To do this, specify the docker-compose key instead of the docker-container-declaration key.

   • Policies:

     deploy_policy:
         max_unavailable: 1
         max_expansion: 0
     scale_policy:
         fixed_scale:
             size: 3
     allocation_policy:
         zones:
             - zone_id: ru-central1-a
     

     Keys:

     Key	Value
     deploy_policy	Deployment policy for instances in the group.
     scale_policy	Scaling policy for instances in the group.
     allocation_policy	Policy for allocating instances across zones and regions.

     Full code for the specification.yaml file:

     name: container-optimized-group
     service_account_id: aje3932acd8avp6edhbt
     description: "This instance group was created from YAML config."
     instance_template:
         service_account_id: aje3932acd8avp6edhbt # ID of the service account to access private Docker images.
         platform_id: standard-v3
         resources_spec:
             memory: 2G
             cores: 2
         boot_disk_spec:
             mode: READ_WRITE
             disk_spec:
                 image_id: fd81a49qficqvt0dthu8
                 type_id: network-hdd
                 size: 32G
         network_interface_specs:
             - network_id: c64mknqgnd8avp6edhbt
               primary_v4_address_spec: {}
         metadata:
             docker-container-declaration: |-
                 spec:
                     containers:
                         - name: nginx
                           image: cr.yandex/mirror/nginx:1.17.4-alpine
                           securityContext:
                             privileged: false
                           tty: false
                           stdin: false
     deploy_policy:
         max_unavailable: 1
         max_expansion: 0
     scale_policy:
         fixed_scale:
             size: 3
     allocation_policy:
         zones:
             - zone_id: ru-central1-a
     

     Note

     To use in specification.yaml the Docker Compose specification, specify the docker-compose key instead of the docker-container-declaration key.

8. Create an instance group in the default folder:

   $ yc compute instance-group create --file specification.yaml
   

   This command creates a group of three similar instances with the following characteristics:

   • Named container-optimized-group.
   • From the latest version of the public Container Optimized Image.
   • With a running Docker container based on cr.yandex/mirror/nginx:1.17.4-alpine.
   • In the default-net network.
   • In the ru-central1-a availability zone.
   • With 2 vCPUs and 2 GB of RAM.
   • With a 32 GB network HDD.