Multiple VSIs on VPC with block storage volume and a load balancer

This module creates any number of VSI accross any number of subnets and connects them with a single load balancer. For this example module, Nginx is installed on all of the virtual servers and publicly available via the Load Balancer.

Table of Contents

1. Setup
2. Server Images
3. Security Group
4. Virtual Servers
5. Storage
6. Load Balancer
7. Module Variables

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Setup

In order to make sure your load balancers are able to work on your subnet, ensure that your ACL rules for the subnets where your VSI will be provisioned are configured to allow for at least the following rules ^[1]:

Inbound/Outbound	Protocol	Source IP	Source Port	Destination IP	Destination Port
Inbound	UDP/TCP	161.26.0.0/16	53, 80, 443, 1688, 8443	AnyIP	AnyPort
Inbound	TCP	AnyIP	AnyPort	AnyIP	56501
Inbound	TCP	AnyIP	443, 10514, 8834	AnyIP	AnyPort
Outbound	UDP/TCP	AnyIP	AnyPort	161.26.0.0/16	53, 80, 443, 1688, 8443
Outbound	TCP	AnyIP	56501	AnyIP	AnyPort
Outbound	TCP	AnyIP	AnyPort	AnyIP	443, 10514, 8834

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Server Images

This module uses Ubuntu 18.04 to install nginx. Use the ibmcloud is images command to check to see what images are available in your region. The image used is set by the image variable. As a default use:

• For Gen 1 use ubuntu-18.04-amd64 or a similar image.
• For Gen 2 use ibm-ubuntu-18-04-1-minimal-amd64-1 or a similar image.

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Security Group

In order to run the installation script a security group must be setup to access the internet to update and install packages. In this example, a group is created to allow all inbound and outbound traffic to the virtual servers. This group is connected to their primary network interface. This group and it's rules can be changed in vsi_module/security_groups.tf

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Virtual Servers

This module will create any number of VSI accross any number of subnets in a given VPC. The virtual servers will require the use of a SSH Public Key that is created from the ssh_public_key variable.

Subnets

The servers can be deployed on any number of subnets within a single vpc. Specify the subnets by name using the subnet_names variable. Use the vsi_per_subnet variable to specify how many virtual servers will be created on each of the subnets.

Virtual Server Setup

For the machine_type variable, use the ibmcloud is instance-profiles command to find an image that will work in your region. As a default use:

• For Gen 1 use bc1-2x8
• For Gen 2 use bx2-2x8

Enable Floating IPs

For testing it's often helpful to attach a floating IP to a Virtual Server for remote access from your local machine. Set the enable_fip variable to true to add a floating IP to all instances created by this module. This will make your Virtual Servers accessable from the public internet.

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Volumes

This module creates a Block Storage volume for each map in the volumes variable for each of the VSI being created and attaches them to the Virtual Servers. These volumes are created in the resource group the Virtual Servers.

Volume maps can contain the following keys:

Key	Type	Required	Description
name	string	true	Name of the volumes to be created
profile	string	true	Profile to use for these volumes
iops	number	false	Total input/output per second. Only use if profile is custom
capacity	number	false	Capacity of volume in GB. Default is 100
encryption_key	string	false	Key to use for encrypting this volume
tags	list(string)	false	A list of tags to attach to these volumes

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Load Balancer

This creates a single load balancer to balance accross all the virtual servers created by this module. The load balancer is composed of four parts:

• Load Balancer
• Load Balancer Back End Pool
• Load Balancer Pool Members
• Load Balancer Listener

Load Balancer Instance

This creates a load balancer resource. This load balancer can be set to either public or private using the type variable

Back End Pool

This creates a pool that will route traffic to the virtual server instances. It will also monitor the health of those instances

Pool Members

This adds the primary_ipv4_address of each virtual server to the pool, and will tell the pool to listen on a specific port. In the example we are installing nginx that runs on port 80

Listener

This creates a listener for the load balancer that will send traffic to the pool. All pool members must be added before the listener will be created

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Module Variables

Variable	Type	Description	Default
ibmcloud_api_key	string	The IBM Cloud platform API key needed to deploy IAM enabled resources
ibm_region	string	IBM Cloud region where all resources will be deployed	us-south
generation	String	Generation of VPC	1
resource_group	string	Name of resource group to create VPC	asset-development
vpc_name	string	Name of VPC
unique_id	string	The IBM Cloud platform API key needed to deploy IAM enabled resources	asset-module-lb
image	string	Image name used for VSI. Run 'ibmcloud is images' to find available images in a region	ibm-ubuntu-18-04-1-minimal-amd64-1
subnet_names	String	A list of subnet names where VSI will be deployed. Must exist within the VPC
vsi_per_subnet	String	Number of VSI instances for each subnet. All VSI will be connected by a single load balancer	1
ssh_public_key	string	ssh public key to use for vsi
machine_type	string	VSI machine type. Run 'ibmcloud is instance-profiles' to get a list of regional profiles. For Gen 1 use bc1-2x8, for Gen 2 use bx2-2x8	bc1-2x8
enable_fip	String	Enable floating IP. Can be true or false	false
type	string	Load Balancer type, can be public or private	public
listener_port	Number	Listener port	80
listener_protocol	string	The listener protocol. Supported values are http, tcp, and https	http
certificate_instance	string	Optional, the CRN of a certificate instance to use with the load balancer.
connection_limit	Number	Optional, connection limit for the listener. Valid range 1 to 15000.	0
algorithm	string	The load balancing algorithm. Supported values are round_robin, or least_connections. This module can be modified to use weighted_round_robin by adding weight to the load balancer pool members.	round_robin
protocol	string	The pool protocol. Supported values are http, and tcp.	http
health_delay	Number	The health check interval in seconds. Interval must be greater than timeout value.	11
health_retries	Number	The health check max retries.	10
health_timeout	Number	The health check timeout in seconds.	10
health_type	string	The pool protocol. Supported values are http, and tcp.	http
pool_member_port	Number	The port number of the application running in the server member.	80