EC2 Status Checks

• They are automated checks to identify hardware and software issues
• There are 2 types of status checks:
  • System Status Checks:
    • Used to monitor problems with AWS systems (software/hardware) issues on the physical host
    • We can check Personal Health Dashboards for any scheduled critical maintenance by AWS to our instances’ hosts
    • As a resolution we can stop and start the affected instances. The instance will be migrated to another host
  • Instance Status Check:
    • Monitor software/network configuration of our instances. For example monitor for invalid network configurations, exhausted memory, etc.
    • As a resolution we can reboot the instance or change the instance configuration

CloudWatch Metrics and Recovery

• CloudWatch Metrics (1 minute interval):
  • StatusCheckFailed_System
  • StatusCheckFailed_Instance
  • StatusCheckFailed (for both)
• Recovery option 1: use a CloudWatch Alarm (preferred)
  • It will recover the instance with the same private/public IP, EIP, metadata and placement group
  • It can send a notification using SNS
• Recovery option 2: use an Auto Scaling Group
  • Set min/max/desired capacity to 1 to recover an instance
  • This wont keep the same private and EIP assigned to the instances