Oracle Cloud Infrastructure Documentation

Attaching an Instance to an Instance Pool

Attach an existing instance to an instance pool, and then select which instances you want to manage as a group.

When you attach an instance to an instance pool, the pool size increases.

Important

If an autoscaling configuration is associated with the instance pool, then ensure that the autoscaling policy defines a maximum pool size that's large enough for the expanded pool by editing the autoscaling policy. If you attach an instance and it causes the pool size to increase above the maximum autoscaling target, then a future autoscaling event might decrease the pool size and delete instances.

If load balancers are attached to the pool, then the instance is also added to the load balancers.

Before You Begin

To attach an instance to an instance pool, all the following things must be true:

  • The instance and the pool are running.
  • The instance is the same machine type as the pool, either virtual machine or bare metal.
  • The instance is in the same availability domain and fault domain as the pool.
  • The instance's primary VNIC is in the same virtual cloud network (VCN) and subnet as the pool.
  • If secondary VNICs are defined, then the instance's secondary VNIC is in the same VCN and subnet as the secondary VNICs used by other instances in the pool.
  • The instance is not attached to another pool.

You must also have the name or OCID  of the instance that you want to attach.

  • To attach an instance to an instance pool:

    • Navigate to the Instance pools list page. If you need help finding the list page, see Listing Instance Pools.
    • Select the name of the instance pool to which you want to attach to an instance to display the details page.

    Perform the following steps depending on the option that you see:

    Option 1

    From the Details tab:

    • Scroll to the Attached instances section, select Attach instance to display the Attach instance to instance pool dialog.
    • In the dialog select the following:
      • Input type: Set the type to either Instance pool name or Instance pool OCID.
      • Instance compartment: Select the compartment.
      • Instance: Select an instance.
    • Select Attach instance.

    Option 2

    In the Resources section, select Attached instances.

    • In the Attached instances section, select Attach instance to display the Attach instance to instance pool dialog.
    • In the dialog select the following:
      • Input type: select by either Instance pool name or Instance pool OCID.
      • Instance compartment: Select the compartment.
      • Instance: Select an instance.
    • Select Attach instance.

  • Use the instance-pool-instance attach command to attach an existing instance to an instance pool.

    oci compute-management instance-pool-instance attach --instance-id <INSTANCE_OCID>
    oci compute-management instance-pool attach --from-json <file://path/to/file.json>

    <file://path/to/file.json> is the path to a JSON file that defines the instance details. For information about how to generate an example of the JSON file, see Advanced JSON Options.

    For a complete list of flags and variable options for the Compute service CLI commands, see the command line reference for Compute.

  • For information about using the API and signing requests, see REST API documentation and Security Credentials. For information about SDKs, see SDKs and the CLI.

    Use the AttachInstancePoolInstance operation to attach an existing instance to an instance pool.