Feature/lab8

.github/pull_request_template.md

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+## Goal
+## Changes
+## Testing
+- [ ] Clear, descriptive PR title
+- [ ] Documentation updated
+- [ ] No secrets committed

labs/submission8.md

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+### Task 1
+
+#### 1.1: Monitor System Resources
+
+I ran `iostat`, but did not capture `htop` / process list output, so exact top 3 applications by CPU and memory are not available from this session.
+
+```bash
+$ iostat -x 1 5
+Linux 6.10.14-linuxkit (9ed6c7fafc01)   03/27/26        _aarch64_       (8 CPU)
+
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+           0.45    0.00    0.20    0.05    0.00   99.29
+
+Device            r/s     rkB/s   rrqm/s  %rrqm r_await rareq-sz     w/s     wkB/s   wrqm/s  %wrqm w_await wareq-sz     d/s     dkB/s   drqm/s  %drqm d_await dareq-sz     f/s f_await  aqu-sz  %util
+vda              8.96    208.63     4.82  34.97    0.18    23.29    3.15    282.06    19.16  85.88    7.92    89.51    0.61   2531.91     0.00   0.00    0.09  4181.40    0.34    0.50    0.03   0.12
+vdb             50.97   2688.55     0.12   0.23    0.16    52.75    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.01   0.10
+
+
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+           0.00    0.00    0.25    0.00    0.00   99.75
+
+Device            r/s     rkB/s   rrqm/s  %rrqm r_await rareq-sz     w/s     wkB/s   wrqm/s  %wrqm w_await wareq-sz     d/s     dkB/s   drqm/s  %drqm d_await dareq-sz     f/s f_await  aqu-sz  %util
+vda              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+vdb              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+
+
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+           0.00    0.00    0.00    0.00    0.00  100.00
+
+Device            r/s     rkB/s   rrqm/s  %rrqm r_await rareq-sz     w/s     wkB/s   wrqm/s  %wrqm w_await wareq-sz     d/s     dkB/s   drqm/s  %drqm d_await dareq-sz     f/s f_await  aqu-sz  %util
+vda              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+vdb              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+
+
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+           0.00    0.00    0.25    0.00    0.00   99.75
+
+Device            r/s     rkB/s   rrqm/s  %rrqm r_await rareq-sz     w/s     wkB/s   wrqm/s  %wrqm w_await wareq-sz     d/s     dkB/s   drqm/s  %drqm d_await dareq-sz     f/s f_await  aqu-sz  %util
+vda              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+vdb              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+
+
+avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+           0.12    0.00    0.99    0.00    0.00   98.88
+
+Device            r/s     rkB/s   rrqm/s  %rrqm r_await rareq-sz     w/s     wkB/s   wrqm/s  %wrqm w_await wareq-sz     d/s     dkB/s   drqm/s  %drqm d_await dareq-sz     f/s f_await  aqu-sz  %util
+vda              0.00      0.00     0.00   0.00    0.00     0.00  136.00  83448.00   970.00  87.70   47.76   613.59    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    6.50   3.40
+vdb              0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00      0.00     0.00   0.00    0.00     0.00    0.00    0.00    0.00   0.00
+```
+
+Top resource consumers:
+- CPU usage: not captured
+- Memory usage: not captured
+- I/O usage: device `vda` had the biggest write burst in the last sample, `vdb` had the biggest read activity in the first sample
+
+#### 1.2: Disk Space Management
+
+```bash
+$ df -h
+Filesystem      Size  Used Avail Use% Mounted on
+overlay         503G   69G  409G  15% /
+tmpfs            64M     0   64M   0% /dev
+shm              64M     0   64M   0% /dev/shm
+/dev/vda1       503G   69G  409G  15% /etc/hosts
+tmpfs           3.9G     0  3.9G   0% /proc/scsi
+tmpfs           3.9G     0  3.9G   0% /sys/firmware
+```
+
+---
+
+```bash
+$ du -h /var | sort -rh | head -n 10
+71M     /var
+69M     /var/lib
+63M     /var/lib/apt/lists
+63M     /var/lib/apt
+6.2M    /var/lib/dpkg
+5.7M    /var/lib/dpkg/info
+1.7M    /var/cache/debconf
+1.7M    /var/cache
+376K    /var/log
+320K    /var/lib/systemd
+```
+
+---
+
+`sudo` was not available in this environment, so I used `find` without `sudo`:
+
+```bash
+$ find /var -type f -exec du -h {} + | sort -rh | head -n 3
+30M     /var/lib/apt/lists/ports.ubuntu.com_ubuntu-ports_dists_noble_universe_binary-arm64_Packages.lz4
+8.1M    /var/lib/apt/lists/ports.ubuntu.com_ubuntu-ports_dists_noble-updates_restricted_binary-arm64_Packages.lz4
+7.8M    /var/lib/apt/lists/ports.ubuntu.com_ubuntu-ports_dists_noble-security_restricted_binary-arm64_Packages.lz4
+```
+
+### Observations and Analysis
+
+- CPU usage was very low in all samples, and `%idle` stayed close to `99-100%`.
+- I/O usage was mostly low, with a short write spike on `vda` and a read spike on `vdb`.
+- `/var` usage is mostly under `/var/lib`, especially `/var/lib/apt/lists`.
+- Top 3 largest files in `/var` were all package list files under `/var/lib/apt/lists`.
+- I think this environment is mostly idle, with occasional package-management related disk activity.
+- To optimize resource usage, I would first clean apt cache / package lists if not needed, avoid unnecessary background writes, and capture process-level data with `htop` or `ps` next time for CPU and memory consumers.
+
+### Task 2
+
+Website chosen for monitoring: `https://example.com`
+
+#### Browser check configuration
+
+Used a browser check for `example.com` with simple content validation.
+
+![browser check config](assets/browser_check_config.png)
+
+#### Successful check result
+
+The check completed successfully.
+
+![successful result](assets/successful_check_result.png)
+
+#### Alert settings
+
+Configured alerts for the check and confirmed email notifications.
+
+![alert settings](assets/page_with_allert_settings.png)
+
+![email confirmation](assets/email_confirmation.png)
+
+#### Dashboard overview
+
+Dashboard with created checks:
+
+![dashboard](assets/dashboard.png)
+
+### Observations and Analysis
+
+- I chose `example.com` because it is public, simple, and stable enough for a basic monitoring demo.
+- I used a browser check because it validates not only availability, but also page content.
+- A success status plus expected page content helps detect both downtime and incorrect responses.
+- Alerting by email is enough for this lab, since it gives immediate notification if the check starts failing.
+- This setup helps maintain website reliability because it checks whether the page is reachable and whether the expected content is still shown.