VSI Autoscale Group

This template creates a VSI autoscale group across any number of subnets. This autoscale group is connected by a VPC Load Balancer.

Table of Contents

1. Prerequisites
2. Network
3. Load Balancer
4. SSH Key
5. Instance Template
6. Instance Group
7. Module Variables

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Prerequisites

This template requires an existing VPC with at least one subnet attached. This example installs NGINX on the VSI and requires the virtual servers in the autoscale group to be able to recieve inbound traffic and send outbound traffic.

To read more about autoscaling on VPC, read the docs here.

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Network

An example security group with two rules is created for the autoscale group. For this example, it creates rules to allow both all inbound and all outbound traffic from the servers in the autoscale group

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Load Balancer

The Virtual Servers in the autoscale group are connected via a VPC Load Balancer. This load balancer is created across all of the subnets where the autoscale group will be created. A back end pool is also created. Once the autoscale group has finished provisioning, a listener will be added to expose the example NGINX application.

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SSH Key

This module creates an ssh key for VPC using the ssh_public_key variable. To use an existing SSH Key, change this block and it's references to a data block.

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Instance Template

To create an autoscaling group, a template for the virtual servers is created. This module attaches it to the first subnet in the list of subnet_ids variable. The template is screated with the SSH Public Key. That key will be used by all of the machines in the autoscale group.

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Instance Group

An autoscale instance group is created based on the instance template. To enable autoscaling, an instance group manager is created. Instance Group Policies are also created to allow for dynamic scaling of the virtual servers

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Module Variables

Account Variables

Variable Name	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
resource_group	string	Name of resource group to create VPC	asset-development
unique_id	string	The IBM Cloud platform API key needed to deploy IAM enabled resources	asset-module-vsi

VPC Variables

Variable Name	Type	Description	Default
vpc_name	string	Name of VPC
subnet_ids	list	A list of subnet ids where the VSI will be deployed

Virtual Server Variables

Variable Name	Type	Description	Default
image	string	Image name used for VSI. Run 'ibmcloud is images' to find available images in a region	ibm-centos-7-6-minimal-amd64-2
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	bx2-8x32
application_port	string	The port number of the application running in the server member.	80

Instace Group Manager Variables

Variable Name	Type	Description	Default
enable_manager	bool	Enable or disable the instance group manager. Default value is true	true
min_instances	number	Minimum of VSI instances for autoscaling group	3
max_instances	number	Maximum number of instances in autoscaling group	9
aggregation_window	number	The time window in seconds to aggregate metrics prior to evaluation.	120
cooldown	number	The duration of time in seconds to pause further scale actions after scaling has taken place.	300
manager_type	string	The type of instance group manager. Default value is autoscale.	autoscale
group_manager_policies	list	A list of policies for your instance group manager	[{ metric_type = "cpu" } { metric_value = 70 }]

Load Balancer Variables

Variable Name	Type	Description	Default
lb_type	string	Load Balancer type, can be public or private	public
algorithm	string	The load balancing algorithm. Supported values are round_robin, weighted_round_robin, and least_connections	round_robin
protocol	string	The pool protocol. Supported values are http, and tcp.	http
health_delay	String	The health check interval in seconds. Interval must be greater than timeout value.	10
health_retries	string	The health check max retries.	10
health_timeout	string	The health check timeout in seconds.	5
health_type	string	The pool protocol. Supported values are http, and tcp.	http
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