LCA ICT Specialism case studies
LCA ICT Specialism · Put your knowledge to work in context.
The LCA ICT Specialism is an associate-level Linux Foundation certification aimed at people who already handle day-to-day ICT support and want their Linux, networking, and automation skills recognised in a structured way. It sits at the entry-to-intermediate boundary: you are expected to be comfortable at a shell, not to be a kernel developer. The LCA ICT Specialism case studies are 5 cases and about 4,230 words.
1The 02:10 OOM Restart Loop on app-prod-03
A monitoring alert fires at 02:10 for app-prod-03, a 4 vCPU / 8 GB Ubuntu 22.04 host running a Java API behind nginx. Load average is 38, but CPU idle is 62%.
916 words, about 5 min2df Says Full, du Says 41G: The fs01 Write Failures
At 09:05 the wiki and GitLab runners on fs01 report write failures. df -h /var shows 98G used of 100G (100%), but du -xsh /var reports only 41G.
828 words, about 4 min3Prague Branch: Login Works, Large Transfers Hang
Users at the Prague branch (192.168.50.0/24) report that the CRM at HQ (10.10.20.15) loads its login page but freezes after authentication. SSH sessions to HQ connect and authenticate, then hang when a user runs ls -l in a large directory.
857 words, about 4 min4The deploy Account Logged In at 03:14
At 07:30 the SIEM flags 4,200 failed SSH logins for root over 40 minutes from three addresses, followed by one successful login as deploy from 185.x at 03:14. deploy is the account CI uses to push releases; it has NOPASSWD: ALL in sudoers and an authorized keys entry the platform team does not recognize.
800 words, about 4 min5The Backup That Only Works When You Run It
A nightly backup job on db02 runs as user backup from crontab: 0 2 /home/backup/backup.sh /var/log/backup.log 2 &1 . Run manually as backup , it produces a 12 GB compressed dump in /home/backup/dumps and uploads it to object storage.
829 words, about 4 min