SSM

-------------- Hybrid Servers ---------------

https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-managed-instance-activation.html?shortFooter=true

**https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-install-managed-linux.html

sudo amazon-ssm-agent -register -code TR9NoCDSDLTQEgIna+l3 -id f787cd1d-7450-46b8-861a-d43d4680790d -region us-east-1
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sudo snap install amazon-ssm-agent --classic
sudo systemctl status snap.amazon-ssm-agent.amazon-ssm-agent.service

A good link:
https://aws.amazon.com/premiumsupport/knowledge-center/systems-manager-ec2-instance-not-appear/


SSM agent for userdata: 
https://aws.amazon.com/premiumsupport/knowledge-center/install-ssm-agent-ec2-linux/


---------------------------------Python script that checks which instances managed through SSM----------------------------- 

import boto3
 
ec2_instances = [i['InstanceId'] for r in boto3.client('ec2').describe_instances()['Reservations'] for i in r['Instances']]
ssm_instances = [i['InstanceId'] for i in boto3.client('ssm').describe_instance_information()['InstanceInformationList']]

print('EC2 instances:')

for count, s in enumerate(ec2_instances, 1):
    print("{0}. {1}".format(count, s))
#print(ec2_instances)

print('SSM managed instances:')
for count, t in enumerate(ssm_instances, 1):
#for t in ssm_instances:
    print("{0}. {1}".format(count, t))
#print(ssm_instances)


print('Unmanaged EC2 instances:')
print(set(ec2_instances) - set(ssm_instances))



- --  - - - - - - - - - - - - - -- - - - - - - -- - - -- Good link for the tutorial 
https://cloudaffaire.com/how-to-add-an-ec2-instance-to-aws-system-manager-ssm/
https://cloudaffaire.com/how-to-add-an-ec2-instance-to-aws-system-manager-ssm/