inno-devops-labs · HNS2112 · Aug 3, 2026 · Aug 4, 2026 · Aug 6, 2026 · Aug 6, 2026
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
@@ -0,0 +1,13 @@
+## Goal
+<!-- What does this PR accomplish? 1 sentence. -->
+
+## Changes
+-
+
+## Testing
+<!-- How did you verify it? -->
+
+## Checklist
+- [ ] Title is a clear sentence (≤ 70 chars)
+- [ ] Commits are signed (`git log --show-signature`)
+- [ ] `submissions/labN.md` updated
diff --git a/.gitignore b/.gitignore
@@ -61,3 +61,5 @@ Thumbs.db
 #   *.sbom.cdx.json, zap-*.html/json, trivy-*.txt   (Lab 9 scan evidence)
 #   flake.nix, flake.lock      (Lab 11)
 #   wasm/main.go, spin.toml, go.sum   (Lab 12)
+data/
+app/data/
diff --git a/evidence/lab4/01-pcap-read.txt b/evidence/lab4/01-pcap-read.txt
@@ -0,0 +1,45 @@
+18:50:14.556151 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [S], seq 852912346, win 65495, options [mss 65495,sackOK,TS val 2230267369 ecr 0,nop,wscale 10], length 0
+E..<..@.@.;.............2.h..........0.........
+..-........
+
+18:50:14.556164 IP 127.0.0.1.8080 > 127.0.0.1.52742: Flags [S.], seq 3354113025, ack 852912347, win 65483, options [mss 65495,sackOK,TS val 407459794 ecr 2230267369,nop,wscale 10], length 0
+E..<..@.@.<.................2.h......0.........
+.IW...-....
+
+18:50:14.556173 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [.], ack 1, win 64, options [nop,nop,TS val 2230267369 ecr 407459794], length 0
+E..4..@.@.;.............2.h........@.(.....
+..-..IW.
+18:50:14.556203 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [P.], seq 1:176, ack 1, win 64, options [nop,nop,TS val 2230267369 ecr 407459794], length 175: HTTP: POST /notes HTTP/1.1
+E.....@.@.;6............2.h........@.......
+..-..IW.POST /notes HTTP/1.1
+Host: localhost:8080
+User-Agent: curl/8.5.0
+Accept: */*
+Content-Type: application/json
+Content-Length: 40
+
+{"title":"lab4","body":"packet capture"}
+18:50:14.556207 IP 127.0.0.1.8080 > 127.0.0.1.52742: Flags [.], ack 176, win 64, options [nop,nop,TS val 407459794 ecr 2230267369], length 0
+E..4.q@.@..P................2.i....@.(.....
+.IW...-.
+18:50:14.556662 IP 127.0.0.1.8080 > 127.0.0.1.52742: Flags [P.], seq 1:208, ack 176, win 64, options [nop,nop,TS val 407459794 ecr 2230267369], length 207: HTTP: HTTP/1.1 201 Created
+E....r@.@...................2.i....@.......
+.IW...-.HTTP/1.1 201 Created
+Content-Type: application/json
+Date: Thu, 06 Aug 2026 15:50:14 GMT
+Content-Length: 94
+
+{"id":6,"title":"lab4","body":"packet capture","created_at":"2026-08-06T15:50:14.556405793Z"}
+
+18:50:14.556696 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [.], ack 208, win 64, options [nop,nop,TS val 2230267369 ecr 407459794], length 0
+E..4..@.@.;.............2.i........@.(.....
+..-..IW.
+18:50:14.556827 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [F.], seq 176, ack 208, win 64, options [nop,nop,TS val 2230267369 ecr 407459794], length 0
+E..4..@.@.;.............2.i........@.(.....
+..-..IW.
+18:50:14.556994 IP 127.0.0.1.8080 > 127.0.0.1.52742: Flags [F.], seq 208, ack 177, win 64, options [nop,nop,TS val 407459794 ecr 2230267369], length 0
+E..4.s@.@..N................2.i....@.(.....
+.IW...-.
+18:50:14.557066 IP 127.0.0.1.52742 > 127.0.0.1.8080: Flags [.], ack 209, win 64, options [nop,nop,TS val 2230267370 ecr 407459794], length 0
+E..4..@.@.;.............2.i........@.(.....
+..-..IW.
diff --git a/evidence/lab4/02-diagnostics.txt b/evidence/lab4/02-diagnostics.txt
@@ -0,0 +1,93 @@
+$ ss -tlnp | head -20
+State  Recv-Q Send-Q Local Address:Port  Peer Address:PortProcess                              
+LISTEN 0      10           0.0.0.0:7070       0.0.0.0:*                                        
+LISTEN 0      50           0.0.0.0:139        0.0.0.0:*                                        
+LISTEN 0      4096       127.0.0.1:10808      0.0.0.0:*                                        
+LISTEN 0      50           0.0.0.0:445        0.0.0.0:*                                        
+LISTEN 0      5            0.0.0.0:902        0.0.0.0:*                                        
+LISTEN 0      32     192.168.100.1:53         0.0.0.0:*                                        
+LISTEN 0      4096       127.0.0.1:11434      0.0.0.0:*                                        
+LISTEN 0      4096   127.0.0.53%lo:53         0.0.0.0:*                                        
+LISTEN 0      4096      127.0.0.54:53         0.0.0.0:*                                        
+LISTEN 0      4096       127.0.0.1:631        0.0.0.0:*                                        
+LISTEN 0      4096       127.0.0.1:33357      0.0.0.0:*                                        
+LISTEN 0      32     192.168.122.1:53         0.0.0.0:*                                        
+LISTEN 0      10              [::]:7070          [::]:*                                        
+LISTEN 0      4096           [::1]:631           [::]:*                                        
+LISTEN 0      4096               *:8080             *:*    users:(("quicknotes",pid=5201,fd=3))
+LISTEN 0      50              [::]:139           [::]:*                                        
+LISTEN 0      50              [::]:445           [::]:*                                        
+LISTEN 0      5               [::]:902           [::]:*                                        
+
+$ ss -tn state established
+Recv-Q Send-Q        Local Address:Port     Peer Address:Port Process
+0      0                 127.0.0.1:10808       127.0.0.1:49374       
+0      0      192.168.0.123%enp5s0:40090 192.227.253.103:50000       
+0      0                 127.0.0.1:39186       127.0.0.1:10808       
+0      0      192.168.0.123%enp5s0:45180 192.227.253.103:50000       
+0      0      192.168.0.123%enp5s0:52388 192.227.253.103:50000       
+0      0      192.168.0.123%enp5s0:52400 192.227.253.103:50000       
+0      0                 127.0.0.1:49374       127.0.0.1:10808       
+0      0                 127.0.0.1:10808       127.0.0.1:39186       
+0      0                 10.33.0.2:53448    207.188.6.17:443         
+
+$ ip -brief addr
+lo               UNKNOWN        127.0.0.1/8 
+enp5s0           UP             192.168.0.123/24 
+wlx9ca2f49134b7  UP             192.168.0.120/24 
+virbr0           DOWN           192.168.122.1/24 
+virbr1           DOWN           192.168.100.1/24 
+docker0          DOWN           172.17.0.1/16 
+tun2             UNKNOWN        10.33.0.2/24 
+
+$ ip route
+default via 192.168.0.1 dev enp5s0 proto dhcp src 192.168.0.123 metric 100 
+default via 192.168.0.1 dev wlx9ca2f49134b7 proto dhcp src 192.168.0.120 metric 600 
+1.0.0.0/8 via 10.33.0.2 dev tun2 
+1.0.0.1 via 10.33.0.2 dev tun2 
+2.0.0.0/7 via 10.33.0.2 dev tun2 
+4.0.0.0/6 via 10.33.0.2 dev tun2 
+8.0.0.0/5 via 10.33.0.2 dev tun2 
+10.33.0.0/24 dev tun2 proto kernel scope link src 10.33.0.2 
+16.0.0.0/4 via 10.33.0.2 dev tun2 
+32.0.0.0/3 via 10.33.0.2 dev tun2 
+64.0.0.0/2 via 10.33.0.2 dev tun2 
+127.0.0.0/8 dev lo proto kernel scope link src 127.0.0.1 metric 30 
+128.0.0.0/1 via 10.33.0.2 dev tun2 
+172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 
+172.29.172.254 via 10.33.0.2 dev tun2 
+192.168.0.0/24 dev enp5s0 proto kernel scope link src 192.168.0.123 metric 100 
+192.168.0.0/24 dev wlx9ca2f49134b7 proto kernel scope link src 192.168.0.120 metric 600 
+192.168.100.0/24 dev virbr1 proto kernel scope link src 192.168.100.1 linkdown 
+192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown 
+
+$ dig +short localhost
+127.0.0.1
+
+$ dig localhost | head -20
+
+; <<>> DiG 9.18.39-0ubuntu0.24.04.5-Ubuntu <<>> localhost
+;; global options: +cmd
+;; Got answer:
+;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18509
+;; flags: qr aa rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
+
+;; OPT PSEUDOSECTION:
+; EDNS: version: 0, flags:; udp: 65494
+;; QUESTION SECTION:
+;localhost.			IN	A
+
+;; ANSWER SECTION:
+localhost.		0	IN	A	127.0.0.1
+
+;; Query time: 0 msec
+;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
+;; WHEN: Thu Aug 06 18:52:47 MSK 2026
+;; MSG SIZE  rcvd: 54
+
+
+$ getent hosts localhost
+127.0.0.1       localhost
+
+$ curl -s -o /dev/null -w "dns=%{time_namelookup} connect=%{time_connect} total=%{time_total}\n" http://localhost:8080/health
+dns=0.000031 connect=0.000240 total=0.000772
diff --git a/evidence/lab4/03-path.txt b/evidence/lab4/03-path.txt
@@ -0,0 +1,26 @@
+$ mtr -rwc 5 localhost
+Start: 2026-08-06T18:53:36+0300
+HOST: hns       Loss%   Snt   Last   Avg  Best  Wrst StDev
+  1.|-- localhost  0.0%     5    0.1   0.1   0.1   0.1   0.0
+
+$ ip link show lo
+1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
+    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
+
+$ cat /proc/sys/net/ipv4/tcp_congestion_control
+cubic
+
+$ ss -tim state established dst 127.0.0.1 | head -20
+Recv-Q Send-Q Local Address:Port  Peer Address:Port Process                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
+0      0          127.0.0.1:10808    127.0.0.1:49374
+	 skmem:(r0,rb170241,t0,tb2626560,f0,w0,o0,bl0,d6) cubic wscale:10,10 rto:201 rtt:0.601/0.329 ato:40 mss:65483 pmtu:65535 rcvmss:20480 advmss:65483 cwnd:27 bytes_sent:1645335 bytes_acked:1645335 bytes_received:1146513 segs_out:585 segs_in:386 data_segs_out:493 data_segs_in:112 send 23.5Gbps lastsnd:31928 lastrcv:34024 lastack:31928 pacing_rate 47Gbps delivery_rate 74.8Gbps delivered:494 app_limited busy:988ms rcv_rtt:640.625 rcv_space:70448 rcv_ssthresh:161157 minrtt:0.007 snd_wnd:325632
+0      0          127.0.0.1:10808    127.0.0.1:35028
+	 skmem:(r0,rb131072,t0,tb2626560,f0,w0,o0,bl0,d1) cubic wscale:10,10 rto:206 rtt:5.112/10.083 ato:40 mss:32768 pmtu:65535 rcvmss:536 advmss:65483 cwnd:10 bytes_sent:12 bytes_acked:12 bytes_received:13 segs_out:4 segs_in:7 data_segs_out:2 data_segs_in:2 send 513Mbps lastsnd:32576 lastrcv:32576 lastack:32535 pacing_rate 1.03Gbps delivery_rate 3.45Gbps delivered:3 app_limited busy:41ms rcv_space:65483 rcv_ssthresh:65483 minrtt:0.076 snd_wnd:65536                                            
+0      0          127.0.0.1:35028    127.0.0.1:10808
+	 skmem:(r0,rb131072,t0,tb2626560,f0,w0,o0,bl0,d0) cubic wscale:10,10 rto:201 rtt:0.133/0.047 ato:40 mss:32768 pmtu:65535 rcvmss:536 advmss:65483 cwnd:10 bytes_sent:13 bytes_acked:14 bytes_received:12 segs_out:7 segs_in:5 data_segs_out:2 data_segs_in:2 send 19.7Gbps lastsnd:32578 lastrcv:32578 lastack:2113 pacing_rate 39.2Gbps delivery_rate 2.57Gbps delivered:3 app_limited rcv_space:65495 rcv_ssthresh:65495 minrtt:0.102 snd_wnd:65536                                                       
+0      0          127.0.0.1:39186    127.0.0.1:10808
+	 skmem:(r0,rb131072,t0,tb2626560,f0,w0,o0,bl0,d0) cubic wscale:10,10 rto:203 rtt:2.618/5.187 ato:40 mss:34304 pmtu:65535 rcvmss:1391 advmss:65483 cwnd:10 bytes_sent:2311 bytes_acked:2312 bytes_received:1680 segs_out:29 segs_in:32 data_segs_out:8 data_segs_in:7 send 1.05Gbps lastsnd:520092 lastrcv:519745 lastack:6210 pacing_rate 2.1Gbps delivery_rate 19.6Gbps delivered:9 app_limited busy:42ms rcv_space:65495 rcv_ssthresh:76663 minrtt:0.014 snd_wnd:68608                                   
+0      0          127.0.0.1:49374    127.0.0.1:10808
+	 skmem:(r0,rb410514,t0,tb2626560,f0,w0,o0,bl0,d0) cubic wscale:10,10 rto:201 rtt:0.256/0.421 ato:40 mss:65483 pmtu:65535 rcvmss:8568 advmss:65483 cwnd:10 bytes_sent:1146513 bytes_acked:1146514 bytes_received:1645335 segs_out:386 segs_in:586 data_segs_out:112 data_segs_in:493 send 20.5Gbps lastsnd:34029 lastrcv:31933 lastack:1603 pacing_rate 40.9Gbps delivery_rate 105Gbps delivered:113 app_limited busy:210ms rcv_rtt:16 rcv_space:134229 rcv_ssthresh:351181 minrtt:0.005 snd_wnd:161792     
+0      0          127.0.0.1:10808    127.0.0.1:39186
+	 skmem:(r0,rb131072,t0,tb2626560,f0,w0,o0,bl0,d17) cubic wscale:10,10 rto:202 rtt:1.9/2.611 ato:40 mss:38400 pmtu:65535 rcvmss:1085 advmss:65483 cwnd:10 bytes_sent:1680 bytes_acked:1680 bytes_received:2311 segs_out:31 segs_in:29 data_segs_out:7 data_segs_in:8 send 1.62Gbps lastsnd:519749 lastrcv:520096 lastack:519749 pacing_rate 3.23Gbps delivery_rate 16.2Gbps delivered:8 app_limited busy:18ms rcv_rtt:4 rcv_space:65483 rcv_ssthresh:68534 minrtt:0.019 snd_wnd:76800                       
diff --git a/evidence/lab4/04-refused.txt b/evidence/lab4/04-refused.txt
@@ -0,0 +1,13 @@
+$ curl -sv http://localhost:9999/health
+* Host localhost:9999 was resolved.
+* IPv6: ::1
+* IPv4: 127.0.0.1
+*   Trying [::1]:9999...
+* Immediate connect fail for ::1: Невозможно назначить запрошенный адрес
+*   Trying 127.0.0.1:9999...
+* connect to 127.0.0.1 port 9999 from 127.0.0.1 port 58714 failed: В соединении отказано
+* Failed to connect to localhost port 9999 after 0 ms: Couldn't connect to server
+* Closing connection
+
+$ ss -tln sport = :9999
+State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
diff --git a/evidence/lab4/05-latency.txt b/evidence/lab4/05-latency.txt
@@ -0,0 +1,33 @@
+$ 20 последовательных запросов, тайминги
+0.000349 0.000828 0.000901
+0.000365 0.000775 0.000841
+0.000207 0.000502 0.000542
+0.000255 0.000540 0.000604
+0.000139 0.000299 0.000324
+0.000157 0.000355 0.000385
+0.000129 0.000285 0.000309
+0.000124 0.000271 0.000295
+0.000119 0.000260 0.000282
+0.000128 0.000273 0.000298
+0.000107 0.000231 0.000250
+0.000119 0.000283 0.000304
+0.000110 0.000246 0.000266
+0.000128 0.000283 0.000307
+0.000098 0.000203 0.000221
+0.000110 0.000232 0.000252
+0.000107 0.000231 0.000254
+0.000111 0.000279 0.000299
+0.000091 0.000213 0.000233
+0.000086 0.000181 0.000196
+
+$ ss -s
+Total: 972
+TCP:   49 (estab 10, closed 21, orphaned 0, timewait 21)
+
+Transport Total     IP        IPv6
+RAW	  3         1         2        
+UDP	  39        35        4        
+TCP	  28        22        6        
+INET	  70        58        12       
+FRAG	  0         0         0        
+
diff --git a/evidence/lab4/06-broken-deploy.txt b/evidence/lab4/06-broken-deploy.txt
@@ -0,0 +1,3 @@
+2026/08/06 18:55:51 quicknotes listening on :8080 (notes loaded: 6)
+2026/08/06 18:55:51 listen: listen tcp :8080: bind: address already in use
+exit status 1
diff --git a/evidence/lab4/07-triage.txt b/evidence/lab4/07-triage.txt
@@ -0,0 +1,19 @@
+=== 1. Симптом: клиент не может подключиться к новому инстансу ===
+$ curl -sv --max-time 3 http://localhost:8080/health
+{"notes":6,"status":"ok"}
+
+
+=== 2. Кто занимает порт 8080 ===
+$ ss -tlnp sport = :8080
+State  Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
+LISTEN 0      4096               *:8080            *:*    users:(("quicknotes",pid=5201,fd=3))
+
+=== 3. Что это за процесс ===
+$ ps -p 5201 -o pid,ppid,etime,cmd
+    PID    PPID     ELAPSED CMD
+   5201    5094       09:29 /tmp/go-build2908606575/b001/exe/quicknotes
+
+=== 4. Когда он стартовал ===
+$ ls -la /proc/5201/cwd
+lrwxrwxrwx 1 hns hns 0 авг  6 18:56 /proc/5201/cwd -> /home/hns/dev/DevOps-Intro/app
+lrwxrwxrwx 1 hns hns 0 авг  6 18:56 /proc/5201/cwd -> /home/hns/dev/DevOps-Intro/app
diff --git a/evidence/lab4/08-fix.txt b/evidence/lab4/08-fix.txt
@@ -0,0 +1,14 @@
+=== Fix: остановить старый инстанс ===
+$ kill 5201
+$ ss -tlnp sport = :8080   (порт должен освободиться)
+State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
+(пусто = порт свободен)
+
+=== Recovery: новый инстанс поднят ===
+$ ss -tlnp sport = :8080
+State  Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
+LISTEN 0      4096               *:8080            *:*    users:(("quicknotes",pid=5820,fd=3))
+
+$ curl -s http://localhost:8080/health
+{"notes":6,"status":"ok"}
+
diff --git a/evidence/lab4/quicknotes.pcap b/evidence/lab4/quicknotes.pcap