by XDK
28. September 2019 01:39
Explanation:
Launch an EC2 instance for which the custom CloudWatch memory metrics need to be generated.
Create an IAM role named "CustomMetricsRole" with a custom policy name "CustomEC2CloudWatch" to establish the interoperability between EC2 instance and CloudWatch as below
Policy : CustomEC2CloudWatch
Permissions:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"cloudwatch:GetMetricStatistics",
"cloudwatch:PutMetricData",
"cloudwatch:GetMetricData",
"ec2:DescribeTags",
"cloudwatch:ListMetrics"
],
"Resource": "*"
}
]
}
Attach IAM role to the EC2 instance
SSH to EC2 instance
$ sudo apt update
$ sudo apt install unzip
$ sudo apt install perl
$ sudo apt install liblwp-protocol-https-perl libdatetime-perl
Download the CloudWatch Monitoring perl scripts for Linux
$ wget http://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.1.zip
$ unzip CloudWatchMonitoringScripts-1.2.1.zip
$ cd aws-scripts-mon
mon-put-instance-data.pl - Collects system metrics on an EC2 instance and sends them to CloudWatch
mon-get-instance-stats.pl - Queries CloudWatch and displays the most resent metrics
AwsSignatureV4.pm - File template for AWS credentials
Push custom metrics from EC2 instance to CloudWatch
$ ./mon-put-instance-data.pl --mem-util --mem-used --mem-avail
Create crontab and add the script to run at every minute intervals.
$ crontab -e
* * * * * /home/ubuntu/aws-scripts-mon/mon-put-instance-data.pl --mem-util --mem-used --mem-avail
To retrive the most recent custom metrics from CloudWatch to EC2 instance
$ ./mon-get-instance-stats.pl
by XDK
26. September 2019 23:05
Setup Auto SSH Login
SSH to Jenkins Master
$ sudo -iu jenkins
Generate Public & Private RSA Key.
$ ssh-keygen -t rsa
public key location : /var/lib/jenkins/.ssh/id_rsa.pub
private key location : /var/lib/jenkins/.ssh/id_rsa
Create .ssh directory on Jenkins Slave 1 from Jenkins Master
$ ssh -i /home/ubuntu/bin/myaccountkey.pem ubuntu@3.91.65.12 mkdir -p .ssh
Attach master public key with slave authorized directory
$ cat .ssh/id_rsa.pub | ssh -i /home/ubuntu/bin/myaccountkey.pem ubuntu@3.91.65.12 'cat >> .ssh/authorized_keys'
Verify connection
$ ssh ubuntu@3.91.65.12
Create .ssh directory on Jenkins Slave 2 from Jenkins Master
$ ssh -i /home/ubuntu/bin/myaccountkey.pem ubuntu@3.95.20.115 mkdir -p .ssh
Attach master public key with slave authorized directory
$ cat .ssh/id_rsa.pub | ssh -i /home/ubuntu/bin/myaccountkey.pem ubuntu@3.95.20.115 'cat >> .ssh/authorized_keys'
Download Jenkins Slave 1 Agent Program on Jenkins Slave 1 Machine
SSH to Jenkins Slave 1
Create bin directory.
$ mkdir ~/bin
Goto bin and download slave.jar from master
$ cd bin
$ wget http://54.81.205.161:8080/jnlpJars/slave.jar
Add Jenkins Slave 1 Machine to Jenkins Master
Login to Jenkins site
Launch Command
$ ssh ubuntu@3.91.65.12 java -jar ./bin/slave.jar
Download Jenkins Slave 2 Agent Program on Jenkins Slave 2 Machine
SSH to Jenkins Slave 2
Create bin directory.
$ mkdir ~/bin
Goto bin and download slave.jar from master
$ cd bin
$ wget http://54.81.205.161:8080/jnlpJars/slave.jar
Add Jenkins Slave 2 Machine to Jenkins Master
Login to Jenkins site
Launch Command
$ ssh ubuntu@3.95.20.115 java -jar ./bin/slave.jar
by XDK
19. September 2019 18:37
by XDK
18. September 2019 22:27
Explanation:
The user data is not executed due to the leading whitespaces in the following format
resource "aws_instance" "Terraform-Demo" {
ami = "${lookup(var.RegionToAmazonAMI, var.Region)}"
instance_type = "t2.micro"
key_name = "myaccountkey"
vpc_security_group_ids = ["${aws_security_group.webserver-sg-2.id}"]
user_data = <<EOF
#cloud-boothook
#! /bin/bash
sudo apt update
sudo apt install -y apache2
IP_ADDR=$(curl http://169.254.169.254/latest/meta-data/public-ipv4)
sudo chmod 777 /var/www/html
sudo echo "Terraform instance 2 with IP IP_ADDR" > /var/www/html/index.html
sudo echo "Terraform instance 2 with IP IP_ADDR -- OK" > /var/www/html/health.html
EOF
provisioner "local-exec" {
command = "echo ${aws_instance.Terraform-Demo.public_ip} > testP.txt"
}
tags = {
Name = "TerraformDemo"
}
}
Solution:
Either add hyphen in <<-EOF to trim the leading whitespaces or remove the whitespaces manually
by XDK
18. September 2019 22:09
Explanation:
EC2 instances launched in the subnet using Terraform or Cloudformation is missing public IPv4 address
Solution:
Add the following argument/property
CloudFormation:
MapPublicIpOnLaunch - Indicates whether instances launched in this subnet receive a public IPv4 address.
PubSubnetZoneA:
Type: 'AWS::EC2::Subnet'
Properties:
AvailabilityZone:
Fn::Select:
- '0'
- Fn::GetAZs:
Ref: 'AWS::Region'
CidrBlock: '10.0.10.0/24'
MapPublicIpOnLaunch: 'True'
VpcId:
Ref: 'VPC'
Tags:
- Key: 'Name'
Value:
'Fn::Join': [ ':', [ 'Public', 'Zone A', !Ref 'AWS::StackName' ] ]
Terraform:
map_public_ip_on_launch - (Optional) Specify true to indicate that instances launched into the subnet should be assigned a public IP address. Default is false.
resource "aws_subnet" "public-subnet-a" {
vpc_id = "${aws_vpc.vpc.id}"
map_public_ip_on_launch = true
cidr_block = "10.0.10.0/24"
availability_zone = "${data.aws_availability_zones.available.names[0]}"
tags = {
Name = "public-subnet-a:${var.labname}"
}
}
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