100 Days of AWS — Day 8— Pushing System logs and Custom Metrics using CloudWatch agent

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Welcome to Day 8 of 100 Days of AWS. The topic for today is Pushing system logs and custom metrics using CloudWatch agent.

This is what we want to achieve today

• Collect the System logs(/var/log/messages and /var/log/secure) and push it to CloudWatch Logs
• Collect custom metrics(Memory, Disk Space, Swap Utilization)

Solution

This can be achieved via in one of the two ways

• AWS Console
• AWS System Manager

What are the Cloudwatch logs?

Amazon CloudWatch Logs is used to monitor, store, and access your log files from Amazon Elastic Compute Cloud (Amazon EC2) instances, AWS CloudTrail, Route 53, DNS Logs and other sources. You can then retrieve the associated log data from CloudWatch Logs.

Scenario1: Perform the step manually

• Collect System as well as application logs
• System metrics(eg: memory, disk, swap utilization)

Step1: Setup IAM Role(CloudWatch agent installed on EC2 instance, require permission to put data and that why we need to setup this role)

• Go to IAM console https://console.aws.amazon.com/iam/home?region=us-west-2#/home
• Roles → Create role → AWS service → EC2
• Search for these two policies (CloudWatchAgentServerPolicy (This is required for the cloudwatch agent to interact with CloudWatch logs)and AmazonSSMFullAccess(To automate the process of cloudwatch agent installation)

• Click on Create role

Step2: Attach cloudwatch-to-ssm role created an above step to an EC2 instance. Don’t forget to click on Save button.

• Install the Cloudwatch agent

$  wget https://s3.amazonaws.com/amazoncloudwatch-agent/linux/amd64/latest/AmazonCloudWatchAgent.zip
$ unzip AmazonCloudWatchAgent.zip
$ sudo ./install.sh
create group cwagent, result: 0
create user cwagent, result: 0

• Finally the major step, invoke the installer. Choose the default option in most of the cases.

$  sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-config-wizard
================================================================
= Welcome to the Amazon CloudWatch Agent Configuration Manager =
=                                                              =
= CloudWatch Agent allows you to collect metrics and logs from =
= your host and send them to CloudWatch. Additional CloudWatch =
= charges may apply.                                           =
================================================================
On which OS are you planning to use the agent?
1. linux
2. windows
3. darwin
default choice: [1]:
1
Trying to fetch the default region based on ec2 metadata...
Are you using EC2 or On-Premises hosts?
1. EC2
2. On-Premises
default choice: [1]:
1
Which user are you planning to run the agent?
1. root
2. cwagent
3. others
default choice: [1]:
1
Do you want to turn on StatsD daemon?
1. yes
2. no
default choice: [1]:
1
Which port do you want StatsD daemon to listen to?
default choice: [8125]
What is the collect interval for StatsD daemon?
1. 10s
2. 30s
3. 60s
default choice: [1]:
What is the aggregation interval for metrics collected by StatsD daemon?
1. Do not aggregate
2. 10s
3. 30s
4. 60s
default choice: [4]:
Do you want to monitor metrics from CollectD? WARNING: CollectD must be installed or the Agent will fail to start
1. yes
2. no
default choice: [1]:
Do you want to monitor any host metrics? e.g. CPU, memory, etc.
1. yes
2. no
default choice: [1]:
Do you want to monitor cpu metrics per core?
1. yes
2. no
default choice: [1]:
Do you want to add ec2 dimensions (ImageId, InstanceId, InstanceType, AutoScalingGroupName) into all of your metrics if the info is available?
1. yes
2. no
default choice: [1]:
Do you want to aggregate ec2 dimensions (InstanceId)?
1. yes
2. no
default choice: [1]:
Would you like to collect your metrics at high resolution (sub-minute resolution)? This enables sub-minute resolution for all metrics, but you can customize for specific metrics in the output json file.
1. 1s
2. 10s
3. 30s
4. 60s
default choice: [4]:
Which default metrics config do you want?
1. Basic
2. Standard
3. Advanced <--Make sure you choose advance then only you will see(Memory,Swap,Disk...)
4. None
default choice: [1]:
3
Current config as follows:
{
"agent": {
"metrics_collection_interval": 60,
"run_as_user": "root"
},
"metrics": {
"aggregation_dimensions": [
[
"InstanceId"
]
],
"append_dimensions": {
"AutoScalingGroupName": "${aws:AutoScalingGroupName}",
"ImageId": "${aws:ImageId}",
"InstanceId": "${aws:InstanceId}",
"InstanceType": "${aws:InstanceType}"
},
"metrics_collected": {
"collectd": {
"metrics_aggregation_interval": 60
},
"cpu": {
"measurement": [
"cpu_usage_idle",
"cpu_usage_iowait",
"cpu_usage_user",
"cpu_usage_system"
],
"metrics_collection_interval": 60,
"resources": [
"*"
],
"totalcpu": false
},
"disk": {
"measurement": [
"used_percent",
"inodes_free"
],
"metrics_collection_interval": 60,
"resources": [
"*"
]
},
"diskio": {
"measurement": [
"io_time",
"write_bytes",
"read_bytes",
"writes",
"reads"
],
"metrics_collection_interval": 60,
"resources": [
"*"
]
},
"mem": {
"measurement": [
"mem_used_percent"
],
"metrics_collection_interval": 60
},
"netstat": {
"measurement": [
"tcp_established",
"tcp_time_wait"
],
"metrics_collection_interval": 60
},
"statsd": {
"metrics_aggregation_interval": 60,
"metrics_collection_interval": 10,
"service_address": ":8125"
},
"swap": {
"measurement": [
"swap_used_percent"
],
"metrics_collection_interval": 60
}
}
}
}
Are you satisfied with the above config? Note: it can be manually customized after the wizard completes to add additional items.
1. yes
2. no
default choice: [1]:
1
Do you have any existing CloudWatch Log Agent (http://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/AgentReference.html) configuration file to import for migration?
1. yes
2. no
default choice: [2]:
Do you want to monitor any log files?
1. yes
2. no
default choice: [1]:
Log file path:
/var/log/secure
Log group name:
default choice: [secure]
Log stream name:
default choice: [{instance_id}]
Log Group Retention in days
1. -1
2. 1
3. 3
4. 5
5. 7
6. 14
7. 30
8. 60
9. 90
10. 120
11. 150
12. 180
13. 365
14. 400
15. 545
16. 731
17. 1827
18. 3653
default choice: [1]:
7
Do you want to specify any additional log files to monitor?
1. yes
2. no
default choice: [1]:
1
Log file path:
/var/log/messages
Log group name:
default choice: [messages]
Log stream name:
default choice: [{instance_id}]
Log Group Retention in days
1. -1
2. 1
3. 3
4. 5
5. 7
6. 14
7. 30
8. 60
9. 90
10. 120
11. 150
12. 180
13. 365
14. 400
15. 545
16. 731
17. 1827
18. 3653
default choice: [1]:
7
Do you want to specify any additional log files to monitor?
1. yes
2. no
default choice: [1]:
2
Saved config file to /opt/aws/amazon-cloudwatch-agent/bin/config.json successfully.
Current config as follows:
{
"agent": {
"metrics_collection_interval": 60,
"run_as_user": "root"
},
"logs": {
"logs_collected": {
"files": {
"collect_list": [
{
"file_path": "/var/log/secure",
"log_group_name": "secure",
"log_stream_name": "{instance_id}",
"retention_in_days": 30
},
{
"file_path": "/var/log/messages",
"log_group_name": "messages",
"log_stream_name": "{instance_id}",
"retention_in_days": 30
}
]
}
}
},
"metrics": {
"aggregation_dimensions": [
[
"InstanceId"
]
],
"append_dimensions": {
"AutoScalingGroupName": "${aws:AutoScalingGroupName}",
"ImageId": "${aws:ImageId}",
"InstanceId": "${aws:InstanceId}",
"InstanceType": "${aws:InstanceType}"
},
"metrics_collected": {
"collectd": {
"metrics_aggregation_interval": 60
},
"cpu": {
"measurement": [
"cpu_usage_idle",
"cpu_usage_iowait",
"cpu_usage_user",
"cpu_usage_system"
],
"metrics_collection_interval": 60,
"resources": [
"*"
],
"totalcpu": false
},
"disk": {
"measurement": [
"used_percent",
"inodes_free"
],
"metrics_collection_interval": 60,
"resources": [
"*"
]
},
"diskio": {
"measurement": [
"io_time",
"write_bytes",
"read_bytes",
"writes",
"reads"
],
"metrics_collection_interval": 60,
"resources": [
"*"
]
},
"mem": {
"measurement": [
"mem_used_percent"
],
"metrics_collection_interval": 60
},
"netstat": {
"measurement": [
"tcp_established",
"tcp_time_wait"
],
"metrics_collection_interval": 60
},
"statsd": {
"metrics_aggregation_interval": 60,
"metrics_collection_interval": 10,
"service_address": ":8125"
},
"swap": {
"measurement": [
"swap_used_percent"
],
"metrics_collection_interval": 60
}
}
}
}
Please check the above content of the config.
The config file is also located at /opt/aws/amazon-cloudwatch-agent/bin/config.json.
Edit it manually if needed.
Do you want to store the config in the SSM parameter store?
1. yes
2. no
default choice: [1]:
1
What parameter store name do you want to use to store your config? (Use 'AmazonCloudWatch-' prefix if you use our managed AWS policy)
default choice: [AmazonCloudWatch-linux]
Trying to fetch the default region based on ec2 metadata...
Which region do you want to store the config in the parameter store?
default choice: [us-east-1]
Which AWS credential should be used to send json config to parameter store?
1. ASIATGNGBM4JE3EICGM5(From SDK)
2. Other
default choice: [1]:
Successfully put config to parameter store AmazonCloudWatch-linux.
Program exits now.

• For Amazon Linux, you need to perform additional step. As you select collectd to collect your metrics we need to install collectd rpm

$ sudo amazon-linux-extras install collectd

• Now run the validation steps

sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json -s
****** processing amazon-cloudwatch-agent ******
/opt/aws/amazon-cloudwatch-agent/bin/config-downloader --output-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --download-source file:/opt/aws/amazon-cloudwatch-agent/bin/config.json --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config default
Successfully fetched the config and saved in /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp
Start configuration validation...
/opt/aws/amazon-cloudwatch-agent/bin/config-translator --input /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.json --input-dir /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d --output /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml --mode ec2 --config /opt/aws/amazon-cloudwatch-agent/etc/common-config.toml --multi-config default
2022/04/12 02:57:26 Reading json config file path: /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.d/file_config.json.tmp ...
Valid Json input schema.
I! Detecting run_as_user...
No csm configuration found.
Configuration validation first phase succeeded
/opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent -schematest -config /opt/aws/amazon-cloudwatch-agent/etc/amazon-cloudwatch-agent.toml
Configuration validation second phase succeeded
Configuration validation succeeded
amazon-cloudwatch-agent has already been stopped
Created symlink from /etc/systemd/system/multi-user.target.wants/amazon-cloudwatch-agent.service to /etc/systemd/system/amazon-cloudwatch-agent.service.
Redirecting to /bin/systemctl restart amazon-cloudwatch-agent.service

• Start the service as mentioned in the last step

$ sudo  /bin/systemctl restart amazon-cloudwatch-agent.service

• If you go to the CloudWatch dashboard https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#metricsV2:graph=~() , you will see the additional Custom namespaces

• Additional metrics like memory , swap utilization and disk used percent.

• Under CloudWatch Log groups you will now see additional groups messages and secure

• With the entries of log populated

• Next time, if we need to configure CloudWatch agent on any host, we can specify the SSM parameter name after cloudwatch agent installation

# sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c ssm:<ssm parmeter name> -s
# In the above case it was AmazonCloudWatch-linux, so our command will look like this
# sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c ssm:AmazonCloudWatch-linux -s