Virtual Private Clouds (VPCs)

You can choose to complete your IBM Spectrum LSF deployment with a new VPC or use an existing one with existing subnets on IBM Spectrum LSF.

You can use IBM Cloud® Virtual Private Cloud as your VPC. IBM Cloud VPC supports creating your own space in IBM Cloud® for a secure, isolated virtual network that combines the security of a private cloud with the availability and scalability of IBM's public cloud. IBM Cloud VPC gives your applications logical isolation from other networks, and provides scalability and security. To make this logical isolation possible, the VPC is divided into subnets that use a range of private IP addresses. You can create subnets in suggested prefix ranges, or bring your own public IP address range (BYOIP) to your IBM Cloud account. By default, all resources within the same VPC can communicate with each other over the private network, regardless of their subnet.

For more details about IBM Cloud VPC, see the IBM Cloud VPC documentation.

Using a new VPC for your IBM Spectrum LSF cluster

If you choose to deploy your IBM Spectrum LSF cluster with a brand-new VPC, then set the vpc_name input value as null during IBM Spectrum LSF cluster deployment. With this setting, the IBM Spectrum LSF cluster deployment automatically creates a brand-new VPC by using the provided address prefix that you provide for the vpc_cidr input value. Make sure that you provide a valid address prefix for the vpc_cidr input value.

With a new VPC, the IBM Spectrum LSF cluster deployment automatically isolates the network, and creates two different subnets under the new VPC by using the vpc_cidr value:

It splits the larger CIDR range from in vpc_cidr, into two different networks ranges based on number of IP addresses needed under that subnet.
After the CIDR ranges are passed in the vpc_cidr, vpc_cluster_private_subnets_cidr_blocks, and vpc_cluster_login_private_subnets_cidr_blocks input values, the IBM Spectrum LSF cluster deployment automatically creates the VPC and subnets. One subnet range with the same CIDR range is used only for the creation of bastion and login nodes. The other subnets are used to create management nodes or VPC file shares and compute nodes.

Since on the vpc_cluster_login_private_subnets_cidr_blocks value is used to create only the bastion and login nodes, use a smaller CIDR. If a larger range is specified, they go unused.

When a new VPC is created, subsequent VPC IDs are attached as an allowed network under the DNS zones. Custom resolvers can also resolve all the DNS entries for the traffic that originates from VPC or subnets.

Using an existing VPC for your IBM Spectrum LSF cluster

If you have existing VPC infrastructure, you can use that VPC for your IBM Spectrum LSF cluster. There are two possible approaches to using an existing VPC:

An existing VPC with existing subnets available to use.
An existing VPC and automatically creating two new subnets from the IBM Spectrum LSF cluster deployment.

If you use your existing VPC for your IBM Spectrum LSF cluster, set the vpc_name input value during IBM Spectrum LSF cluster deployment with the name of your existing VPC. With this setting, the IBM Spectrum LSF cluster deployment automatically skips creating a new VPC and uses the one you specify and its existing VPC details for all networking.

With an existing VPC, you can also choose to make use of existing subnets to create IBM Spectrum LSF cluster nodes. Cluster deployment needs two subnets:

Provide a larger subnet ID for the cluster_subnet_ids dployment inout value, as it is used to create all management nodes or VPC file shares, and the compute nodes.
Provide another subnet ID for the login_subnet_id to create the bastion and login nodes.

If you have an existing VPC but there are no existing subnets to use, then provide the available valid CIDR range for the vpc_cluster_private_subnets_cidr_blocks and vpc_cluster_login_private_subnets_cidr_blocks IBM Spectrum LSF cluster deployment input values. The deployment creates two new subnets under your provided existing VPC.

When you provide existing VPC detail, subsequent VPC IDs are attached as an allowed network under the DNS zones. Custom resolvers can also resolve all the DNS entries for the traffic that originates from VPC or subnets.