docs(is_instance_group_manager): added example and related documents (IBM-Cloud#6296)

* docs(is_instance_group_manager): added example and related documents

* docs(is_instance_group_manager): added example and related documents

Author: uibm

website/docs/r/is_instance_group_manager.html.markdown

@@ -22,7 +22,9 @@ provider "ibm" {
 ```
 
 ## Example usage
-The following example creates an instance group manager.
+
+### Basic Instance Group Manager
+The following example creates a basic instance group manager.
 
 ```terraform
 resource "ibm_is_vpc" "example" {
@@ -36,14 +38,18 @@ resource "ibm_is_subnet" "example" {
   ipv4_cidr_block = "10.240.64.0/28"
 }
 
+data "ibm_is_image" "ubuntu" {
+  name = "ibm-ubuntu-20-04-6-minimal-amd64-6"
+}
+
 resource "ibm_is_ssh_key" "example" {
   name       = "example-ssh"
-  public_key = "SSH_KEY"
+  public_key = file("~/.ssh/id_ed25519.pub")
 }
 
 resource "ibm_is_instance_template" "example" {
   name    = "example-template"
-  image   = ibm_is_image.example.id
+  image   = data.ibm_is_image.ubuntu.id
   profile = "bx2-8x32"
 
   primary_network_interface {
@@ -80,22 +86,231 @@ resource "ibm_is_instance_group_manager" "example" {
   min_membership_count = 1
 }
 
-resource "ibm_is_instance_group_manager" "example" {
+resource "ibm_is_instance_group_manager" "scheduled" {
   name           = "example-instance-group-manager"
   instance_group = ibm_is_instance_group.example.id
   manager_type   = "scheduled"
   enable_manager = true
 }
 ```
 
+### Example with Load Balancer, Autoscaling, and Scheduled Managers
+An example to set up an instance group with both autoscaling and scheduled managers working together with a load balancer, addresses the need of both automatic scaling based on metrics and scheduled scaling for predictable workload patterns.
+
+```terraform
+
+resource "ibm_is_instance_template" "webserver" {
+  name    = "${var.prefix}-webserver-template"
+  image   = data.ibm_is_image.ubuntu.id
+  profile = "cx2-2x4"
+
+  primary_network_interface {
+    subnet          = ibm_is_subnet.example.id
+    security_groups = [ibm_is_security_group.webserver.id]
+  }
+
+  vpc  = ibm_is_vpc.example.id
+  zone = ibm_is_subnet.example.zone
+  keys = [ibm_is_ssh_key.example.id]
+
+  # User data for web server setup
+  user_data = base64encode(<<-EOF
+    #!/bin/bash
+    apt-get update
+    apt-get install -y nginx
+    systemctl start nginx
+    systemctl enable nginx
+    
+    # Configure nginx for health checks
+    echo "server { listen 80; location /health { return 200 'OK'; } }" > /etc/nginx/sites-available/health
+    ln -s /etc/nginx/sites-available/health /etc/nginx/sites-enabled/
+    systemctl reload nginx
+  EOF
+  )
+}
+
+# Load Balancer for the instance group
+resource "ibm_is_lb" "webapp_lb" {
+  name           = "${var.prefix}-load-balancer"
+  subnets        = [ibm_is_subnet.example.id]
+  type           = "private"
+  
+  # Enable logging for monitoring (optional)
+  logging = true
+}
+
+# Backend pool for the load balancer
+resource "ibm_is_lb_pool" "webapp_backend_pool" {
+  name           = "${var.prefix}-backend-pool"
+  lb             = ibm_is_lb.webapp_lb.id
+  algorithm      = "round_robin"
+  protocol       = "http"
+  health_delay   = 60
+  health_retries = 5
+  health_timeout = 30
+  health_type    = "http"
+  health_monitor_url     = "/health"
+}
+
+# Load balancer listener
+resource "ibm_is_lb_listener" "webapp_listener" {
+  lb           = ibm_is_lb.webapp_lb.id
+  port         = 80
+  protocol     = "http"
+  default_pool = ibm_is_lb_pool.webapp_backend_pool.id
+}
+
+# Security group for web servers
+resource "ibm_is_security_group" "webserver" {
+  name           = "${var.prefix}-webserver-sg"
+  vpc            = ibm_is_vpc.example.id
+}
+
+resource "ibm_is_security_group_rule" "webserver_http" {
+  group     = ibm_is_security_group.webserver.id
+  direction = "inbound"
+  remote    = "0.0.0.0/0"
+  tcp {
+    port_min = 80
+    port_max = 80
+  }
+}
+
+resource "ibm_is_security_group_rule" "webserver_ssh" {
+  group     = ibm_is_security_group.webserver.id
+  direction = "inbound"
+  remote    = "0.0.0.0/0"
+  tcp {
+    port_min = 22
+    port_max = 22
+  }
+}
+
+# Instance Group with Load Balancer integration
+resource "ibm_is_instance_group" "webapp_ig" {
+  name              = "${var.prefix}-instance-group"
+  instance_template = ibm_is_instance_template.webserver.id
+  instance_count    = 3
+  subnets           = [ibm_is_subnet.example.id]
+  # Load balancer integration
+  application_port     = 80
+  load_balancer        = ibm_is_lb.webapp_lb.id
+  load_balancer_pool   = element(split("/", ibm_is_lb_pool.webapp_backend_pool.id), 1)
+  
+  # Lifecycle management to prevent conflicts with auto-scaling
+  lifecycle {
+    ignore_changes = [
+      instance_count,
+    ]
+  }
+  
+  timeouts {
+    create = "15m"
+    delete = "15m"
+    update = "10m"
+  }
+}
+
+# Autoscaling Manager - Handles automatic scaling based on metrics
+resource "ibm_is_instance_group_manager" "webapp_autoscaler" {
+  name               = "${var.prefix}-autoscale-manager"
+  aggregation_window = 120
+  instance_group     = ibm_is_instance_group.webapp_ig.id
+  
+  cooldown             = 120
+  manager_type         = "autoscale"
+  enable_manager       = true
+  max_membership_count = 10
+  min_membership_count = 2
+}
+
+# CPU-based scaling policy for the autoscaler
+resource "ibm_is_instance_group_manager_policy" "webapp_cpu_policy" {
+  name                   = "${var.prefix}-cpu-scaling-policy"
+  instance_group         = ibm_is_instance_group.webapp_ig.id
+  instance_group_manager = ibm_is_instance_group_manager.webapp_autoscaler.manager_id
+  metric_type            = "cpu"
+  metric_value           = 70
+  policy_type            = "target"
+}
+
+# Memory-based scaling policy (optional additional policy)
+resource "ibm_is_instance_group_manager_policy" "webapp_memory_policy" {
+  name                   = "${var.prefix}-memory-scaling-policy"
+  instance_group         = ibm_is_instance_group.webapp_ig.id
+  instance_group_manager = ibm_is_instance_group_manager.webapp_autoscaler.manager_id
+  metric_type            = "memory"
+  metric_value           = 80
+  policy_type            = "target"
+}
+
+# Scheduled Manager - Handles time-based scaling actions
+resource "ibm_is_instance_group_manager" "webapp_scheduler" {
+  name           = "${var.prefix}-scheduled-manager"
+  instance_group = ibm_is_instance_group.webapp_ig.id
+  manager_type   = "scheduled"
+  enable_manager = true
+}
+
+# Scheduled action to scale down during off-peak hours (5 PM daily)
+resource "ibm_is_instance_group_manager_action" "webapp_scale_down_evening" {
+  name                   = "${var.prefix}-scale-down-evening"
+  instance_group         = ibm_is_instance_group.webapp_ig.id
+  instance_group_manager = ibm_is_instance_group_manager.webapp_scheduler.manager_id
+  
+  # target_manager specifies which manager's limits to modify
+  target_manager = ibm_is_instance_group_manager.webapp_autoscaler.manager_id
+  
+  # Scale down at 5:05 PM daily (17:05 UTC)
+  cron_spec = "05 17 * * *"
+  
+  # Adjust the autoscaler's limits for off-peak hours
+  min_membership_count = 2
+  max_membership_count = 4
+}
+
+# Scheduled action to scale up for peak hours (8 AM daily)
+resource "ibm_is_instance_group_manager_action" "webapp_scale_up_morning" {
+  name                   = "${var.prefix}-scale-up-morning"
+  instance_group         = ibm_is_instance_group.webapp_ig.id
+  instance_group_manager = ibm_is_instance_group_manager.webapp_scheduler.manager_id
+  
+  # target_manager specifies which manager's limits to modify
+  target_manager = ibm_is_instance_group_manager.webapp_autoscaler.manager_id
+  
+  # Scale up at 8:05 AM daily (08:05 UTC)
+  cron_spec = "05 08 * * *"
+  
+  # Adjust the autoscaler's limits for peak hours
+  min_membership_count = 3
+  max_membership_count = 10
+}
+
+# Weekend scale-down action (Saturday midnight)
+resource "ibm_is_instance_group_manager_action" "webapp_weekend_scale_down" {
+  name                   = "${var.prefix}-weekend-scale-down"
+  instance_group         = ibm_is_instance_group.webapp_ig.id
+  instance_group_manager = ibm_is_instance_group_manager.webapp_scheduler.manager_id
+  
+  target_manager = ibm_is_instance_group_manager.webapp_autoscaler.manager_id
+  
+  # Scale down at midnight on Saturday (00:05 UTC)
+  cron_spec = "05 00 * * 6"
+  
+  min_membership_count = 1
+  max_membership_count = 3
+}
+
+```
+
 ## Argument reference
 Review the argument references that you can specify for your resource. 
 
 - `aggregation_window` - (Optional, Integer) The time window in seconds to aggregate metrics prior to evaluation.
 - `cooldown` - (Optional, Integer) The duration of time in seconds to pause further scale actions after scaling has taken place.
 - `enable_manager` - (Optional, Bool)  Enable or disable the instance group manager. Default value is **true**.
 - `instance_group` - (Required, String) The instance group ID where instance group manager is created.
-- `manager_type` - (Optional, String) The type of instance group manager. Default value is `autoscale`.
+- `manager_type` - (Optional, String) The type of instance group manager. Default value is `autoscale`. Valid values are `autoscale` and `scheduled`.
 - `max_membership_count`- (Required, Integer) The maximum number of members in a managed instance group.
 - `min_membership_count` - (Optional, Integer) The minimum number of members in a managed instance group. Default value is `1`.
 - `name` - (Optional, String) The name of the instance group manager.
@@ -116,3 +331,11 @@ The `ibm_is_instance_group_manager` resource can be imported by using the instan
 ```
 $ terraform import ibm_is_instance_group_manager.manager r006-eea6b0b7-babd-47a8-82c5-ad73d1e10bef/r006-160b9a68-58c8-4ec3-84b0-ad553c111115a
 ```
+
+## Related Resources
+
+- [`ibm_is_instance_group`](https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/is_instance_group) - Creates the instance group
+- [`ibm_is_instance_group_manager_policy`](https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/is_instance_group_manager_policy) - Defines scaling policies for autoscale managers
+- [`ibm_is_instance_group_manager_action`](https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/is_instance_group_manager_action) - Creates scheduled actions for scheduled managers
+- [`ibm_is_lb`](https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/is_lb) - Load balancer for distributing traffic
+- [`ibm_is_lb_pool`](https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/is_lb_pool) - Backend pool for load balancer