Auto Scaling with VPC
This example uses the CLI version 1.0.61.2 (API 2011-01-01). There is now a newer version of the CLI.
Overall notes:
1. Create an image
(aka: gold image) that has a health check on it that consists of a simple
static HTML page such as a ping.html or an index.html.
2. The ELB (need an ELB
before creating Auto Scaling group) hat has the instances running from your
gold image AMI created in step 1. Could potentially (nothing is preventing you
from doing) create a auto scale launch configuration (step 6 in process below)
with an AMI that is different, with a different instance type as instance type
is another parameter of your launch configuration, than the instance that will
be part of your auto scaling group. Both
are possible but most will have the same AMI (gold image, so you know you have
a health check) and the same instance type.
3. Before you create
the ELB you should have instances running of the gold image to make sure the ELB is working properly.
To provide true HA, make sure to put the instances in two AZs. (for
example: us-west-2a, us-west-2b)
4. When creating elb that is using subnets, limitation on ELB is that only
one subnet per AZ is allowed.
5. When creating
autoscaling group (as-create-auto-scaling-group)
need to make sure to specific the VPC subnets
and AZs. The VPC subnets need to be in
the AZs specified in the AZ parameter for command.
Steps:
Prework:
1. Identify the VPC : For example, VPC:
vpc-9b120cf2
2. Add subnets : In this
case, using two public subnets. I had to create the second one (subnet) which was
private by default and I had to add an igw to make it public.
3. Subnets -
A. Subnet: subnet-9f120cf6
CIDR:
10.0.0.0/24 VPC: vpc-9b120cf2 Availability
Zone: us-west-2a
B.
Subnet: subnet-8c130de5
CIDR:
10.0.5.0/24 VPC: vpc-9b120cf2 Availability
Zone: us-west-2b
4. Luanch two instances from AMI that has Apache installed with ping.html (or some other file) as a health check. One instance in subnet A and the other in subnet B.
5. Create an ELB with the two instances across subnets. ELB is healthy with two instances running in
two AZs in two different public subnets. Limitation on ELB is that one subnet
per AZ.
6. Auto Scaling:
A. as-create-launch-config
vpcautoscaling-as-lc --image-id ami-dcd344ec --instance-type t1.micro --key AutoScalingKey
B. as-create-auto-scaling-group vpcautoscaling-as-grp
--launch-configuration vpcautoscaling-as-lc
--min-size 4 --max-size 12 --load-balancers VpcautoscalingAutoScalingELB
--vpc-zone-identifier subnet-9f120cf6,subnet-8c130de5 --availability-zones us-west-2a,us-west-2b
C. as-describe-auto-scaling-groups --headers
output of command:
INSTANCE INSTANCE-ID
AVAILABILITY-ZONE STATE STATUS
LAUNCH-CONFIG
INSTANCE i-3af6e708
us-west-2b InService Healthy
vpcautoscaling-as-lc
INSTANCE i-3cf6e70e
us-west-2a InService Healthy
vpcautoscaling-as-lc
INSTANCE i-3ef6e70c
us-west-2a InService Healthy
vpcautoscaling-as-lc
INSTANCE i-38f6e70a
us-west-2b InService Healthy
vpcautoscaling-as-lc
D. as-put-scaling-policy vpcautoscaling-scale-out-policy
--auto-scaling-group vpcautoscaling-as-grp --adjustment=30 --type
PercentChangeInCapacity
ARN:
arn:aws:autoscaling:us-west-2:649163059618:scalingPolicy:69270ce4-3350-48f4-9d6f-71bc64225554:autoScalingGroupName/vpcautoscaling-as-grp:policyName/vpcautoscaling-scale-out-policy
E. as-put-scaling-policy vpcautoscaling-scale-in-policy
--auto-scaling-group vpcautoscaling-as-grp --adjustment=1 --type PercentChangeInCapacity
ARM -
arn:aws:autoscaling:us-west-2:649163059618:scalingPolicy:d9a6780b-3319-4b00-98f1-e98dcfc68d82:autoScalingGroupName/vpcautoscaling-as-grp:policyName/vpcautoscaling-scale-in-policy
F. mon-put-metric-alarm --alarm-name AddCapacity --metric-name CPUUtilization
--namespace "AWS/EC2" --statistic "Average"
--evaluation-periods 6 --period 120 --threshold 80 --comparison-operator
GreaterThanOrEqualToThreshold --dimensions "AutoScalingGroupName=vpcautoscaling-as-grp"
--alarm-actions arn:aws:autoscaling:us-west-2:649163059618:scalingPolicy:69270ce4-3350-48f4-9d6f-71bc64225554:autoScalingGroupName/vpcautoscaling-as-grp:policyName/vpcautoscaling-scale-out-policy
G. mon-put-metric-alarm --alarm-name RemoveCapacity --metric-name
CPUUtilization --namespace "AWS/EC2" --statistic "Average"
--evaluation-periods 2 --period 120 --threshold 40 --comparison-operator
LessThanOrEqualToThreshold --dimensions "AutoScalingGroupName=vpcautoscaling-as-grp"
--alarm-actions arn:aws:autoscaling:us-west-2:649163059618:scalingPolicy:d9a6780b-3319-4b00-98f1-e98dcfc68d82:autoScalingGroupName/vpcautoscaling-as-grp:policyName/vpcautoscaling-scale-in-policy
H. as-describe-policies
--auto-scaling-group vpcautoscaling-as-grp —headers