Fix CloudWatch agent binary log files and startup issues #216
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btmp and wtmp are binary files in utmp format that CloudWatch agent cannot parse as text logs, resulting in garbled data in the log streams. Authentication data is already captured in auth.log in a parseable format. Changes: - Remove btmp/wtmp entries from CloudWatch agent templates - Remove utmp group from cwagent user (no longer needed) - Remove duplicate DiskSpaceUsed metric - Fix agent startup: remove -s flag from amazon-cloudwatch-agent-ctl and add notify to Service resource for proper systemd group resolution - Update logrotate postrotate comment for clarity Applied to modules/profile and propagated to sandbox and development environments.
infrahouse8
approved these changes
Dec 23, 2025
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Summary
Details
Binary log files removed
btmpandwtmpare binary files in utmp format that CloudWatch agent cannot parse as text logs, resulting in garbled data in log streams. Authentication data is already captured inauth.login a parseable format, so these files are redundant.Agent startup fix
Removed the
-sflag fromamazon-cloudwatch-agent-ctlcommand and addednotify => Service[...]to ensure the agent starts via systemd. This fixes an issue where the agent process would start without supplementary groups (likeadm) because the-sflag bypasses systemd's group resolution.Cleanup
utmpgroup from cwagent user (no longer needed without btmp/wtmp)DiskSpaceUsedmetric from sandbox environmentTest plan
cat /proc/$(pgrep -f amazon-cloudwatch)/status | grep Groups