Feature/lab8

.github/pull_request_template.md

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+## Goal
+What is the purpose of this PR?
+
+## Changes
+What was changed?
+
+## Testing
+How was it tested?
+
+### Checklist
+- [ ] Clear, descriptive PR title
+- [ ] Documentation/README updated (if needed)
+- [ ] No secrets or large temporary files committed

labs/artifacts/lab8/df-h.txt

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+Filesystem      Size  Used Avail Use% Mounted on
+tmpfs           593M  1.5M  591M   1% /run
+/dev/sda2        25G   13G   11G  55% /
+tmpfs           2.9G     0  2.9G   0% /dev/shm
+tmpfs           5.0M  8.0K  5.0M   1% /run/lock
+tmpfs           593M  116K  593M   1% /run/user/1000

labs/artifacts/lab8/du-var-top10.txt

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+3.1G	/var
+2.8G	/var/lib
+2.2G	/var/lib/snapd
+1.2G	/var/lib/snapd/cache
+1.1G	/var/lib/snapd/snaps
+254M	/var/lib/apt/lists
+254M	/var/lib/apt
+181M	/var/cache
+177M	/var/lib/docker
+176M	/var/lib/docker/overlay2

labs/artifacts/lab8/iotop-active.txt

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+   6011 be/4 root        0.00 B/s  408.18 M/s ?unavailable?  dd if=/dev/zero of=/tmp/lab8-io-test.bin bs=8M count=128 status=none
+   6011 be/4 root        0.00 B/s  251.94 M/s ?unavailable?  dd if=/dev/zero of=/tmp/lab8-io-test.bin bs=8M count=128 status=none
+   6015 be/4 root        0.00 B/s    3.85 K/s ?unavailable?  python3 /usr/sbin/iotop -b -o -n 5 -qqq
+   6012 be/4 root       30.77 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/snaps/gnome-42-2204_247.snap of=/dev/null bs=4M status=none
+   6013 be/4 root       30.77 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d of=/dev/null bs=4M status=none
+   6011 be/4 root        0.00 B/s  101.88 M/s ?unavailable?  dd if=/dev/zero of=/tmp/lab8-io-test.bin bs=8M count=128 status=none
+   6012 be/4 root       38.45 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/snaps/gnome-42-2204_247.snap of=/dev/null bs=4M status=none
+   6013 be/4 root       30.76 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d of=/dev/null bs=4M status=none
+   6011 be/4 root        0.00 B/s  100.00 M/s ?unavailable?  dd if=/dev/zero of=/tmp/lab8-io-test.bin bs=8M count=128 status=none
+   6012 be/4 root       31.37 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/snaps/gnome-42-2204_247.snap of=/dev/null bs=4M status=none
+   6013 be/4 root       39.22 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d of=/dev/null bs=4M status=none
+   6012 be/4 root       21.93 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/snaps/gnome-42-2204_247.snap of=/dev/null bs=4M status=none
+   6013 be/4 root       30.34 M/s    0.00 B/s ?unavailable?  dd if=/var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d of=/dev/null bs=4M status=none

labs/artifacts/lab8/pidstat-d-1-5.txt

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+Linux 6.17.0-19-generic (andrey-VirtualBox) 	05/10/2026 	_x86_64_	(2 CPU)
+
+05:53:04 PM   UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command
+
+05:53:05 PM   UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command
+
+05:53:06 PM   UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command
+
+05:53:07 PM   UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command
+
+05:53:08 PM   UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command
+
+Average:      UID       PID   kB_rd/s   kB_wr/s kB_ccwr/s iodelay  Command

labs/artifacts/lab8/run-timestamp.txt

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+2026-05-10 17:52:59 MSK

labs/artifacts/lab8/top-cpu.txt

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+    PID COMMAND         %CPU %MEM
+   5567 ps               250  0.0
+   2272 gnome-shell      1.2  5.8
+   5421 packagekitd      0.7  0.3
+   3372 kworker/1:0-eve  0.2  0.0
+   1175 happd            0.2  0.2
+    891 polkitd          0.1  0.2
+      1 systemd          0.1  0.2
+   2565 ibus-extension-  0.1  0.4
+   5143 sshd             0.1  0.1
+    895 snapd            0.1  0.6
+    868 dbus-daemon      0.1  0.1
+   1189 containerd       0.1  0.8
+   1224 dockerd          0.1  1.2
+     24 ksoftirqd/1      0.0  0.0

labs/artifacts/lab8/top-mem.txt

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+    PID COMMAND         %MEM %CPU
+   2272 gnome-shell      5.8  1.2
+   2936 mutter-x11-fram  1.7  0.0
+   2809 gsd-xsettings    1.3  0.0
+   1224 dockerd          1.2  0.1
+   2358 Xwayland         1.1  0.0
+   2403 evolution-alarm  1.0  0.0
+   1189 containerd       0.8  0.1
+   2359 evolution-sourc  0.7  0.0
+   2930 xdg-desktop-por  0.6  0.0
+    895 snapd            0.6  0.1
+   3070 update-notifier  0.5  0.0
+   2731 evolution-addre  0.5  0.0
+   2686 snapd-desktop-i  0.5  0.0
+   2565 ibus-extension-  0.4  0.1

labs/artifacts/lab8/var-largest-3-files.txt

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+607M	/var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d
+532M	/var/lib/snapd/snaps/gnome-42-2204_247.snap
+395M	/var/lib/snapd/cache/651a6f21a71dfa0a5303df4e7e5661ba7a9213d5177cdc99ae3f0a1798e47bd6ee4b3805063e8f86da1f7b1b8ce9eacb

labs/submission8.md

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+# Lab 8 - Submission
+
+## Task 1 - Key Metrics for SRE and System Analysis
+
+### Commands used
+
+```bash
+sudo apt-get update -y
+sudo apt-get install -y htop sysstat iotop
+
+ps -eo pid,comm,%cpu,%mem --sort=-%cpu | head -n 15
+ps -eo pid,comm,%mem,%cpu --sort=-%mem | head -n 15
+iostat -x 1 5
+pidstat -d 1 5
+
+df -h
+sudo du -h /var | sort -rh | head -n 10
+sudo find /var -type f -exec du -h {} + | sort -rh | head -n 3
+```
+
+### Key results
+
+Top 3 CPU consumers (excluding short-lived `ps`):
+1. `gnome-shell` (~1.2% CPU)
+2. `packagekitd` (~0.7% CPU)
+3. `happd` (~0.2% CPU)
+
+Top 3 memory consumers:
+1. `gnome-shell` (~5.8% MEM)
+2. `mutter-x11-frames` (~1.7% MEM)
+3. `gsd-xsettings` (~1.3% MEM)
+
+Top 3 I/O consumers (`iotop` under controlled load):
+1. `dd if=/dev/zero of=/tmp/lab8-io-test.bin ...` (write up to ~408 MB/s)
+2. `dd if=/var/lib/snapd/snaps/gnome-42-2204_247.snap ...` (read ~21-38 MB/s)
+3. `dd if=/var/lib/snapd/cache/... ...` (read ~30-39 MB/s)
+
+Top 3 largest files in `/var`:
+1. `607M /var/lib/snapd/cache/6b8f0b8920d12519d7c5e677950a231810fa253e34962f312b3dfa58af9d91eeab9d5c1b3483cf0da6df66f23f3f5f8d`
+2. `532M /var/lib/snapd/snaps/gnome-42-2204_247.snap`
+3. `395M /var/lib/snapd/cache/651a6f21a71dfa0a5303df4e7e5661ba7a9213d5177cdc99ae3f0a1798e47bd6ee4b3805063e8f86da1f7b1b8ce9eacb`
+
+Artifacts:
+- `labs/artifacts/lab8/top-cpu.txt`
+- `labs/artifacts/lab8/top-mem.txt`
+- `labs/artifacts/lab8/iostat-x-1-5.txt`
+- `labs/artifacts/lab8/pidstat-d-1-5.txt`
+- `labs/artifacts/lab8/iotop-active.txt`
+- `labs/artifacts/lab8/df-h.txt`
+- `labs/artifacts/lab8/du-var-top10.txt`
+- `labs/artifacts/lab8/var-largest-3-files.txt`
+
+### Analysis
+
+The system stayed mostly idle on CPU, with desktop services as the primary steady consumers. Most disk usage in `/var` is concentrated in `snapd` cache and snap packages, while Docker storage usage is smaller in this snapshot.
+
+### Reflection
+
+Main optimization actions:
+- Clean snap cache and remove unused snap revisions.
+- Keep periodic Docker image cleanup.
+- Track baseline CPU/I/O/storage trends and alert on deviations.
+
+---
+
+## Task 2 - Practical Website Monitoring Setup (Checkly)
+
+### Monitored website
+
+- `https://example.com`
+
+### Configured checks
+
+1. API Check
+   - URL: `https://example.com`
+   - Assertion: status code `200`
+   - Frequency: every `5` minutes
+
+2. Browser Check
+   - URL: `https://example.com`
+   - Validation: page title contains `Example Domain`
+   - Validation: text `Example Domain` is visible
+
+3. Alerts
+   - Alert on failed checks
+   - Alert on high latency threshold
+   - Notification channel: email
+
+### Evidence (screenshots)
+
+- `labs/artifacts/lab8/screenshots/checkly-browser-config.png`
+- `labs/artifacts/lab8/screenshots/checkly-success-result.png`
+- `labs/artifacts/lab8/screenshots/checkly-alert-settings.png`
+- `labs/artifacts/lab8/screenshots/checkly-dashboard-overview.png`
+
+### Analysis
+
+The setup combines availability checks (API) and user-facing behavior checks (Browser). This reduces blind spots where endpoint status is green but user experience is degraded.
+
+### Reflection
+
+This monitoring approach improves incident detection speed and helps reduce MTTR by alerting on both downtime and performance issues.

labs/test

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+test commit