systemd-thoughts

ssh-reverse-tunnel-service.md

@@ -0,0 +1,37 @@
+# systemd cheat sheet
+## ssh systemd rerverse shell as service
+    
+    - persistent reverse SSH connection with systemd
+
+
+
+```
+    -g  Allows remote hosts to connect to local forwarded ports
+    -N  Do not execute a remote command
+    -T  Disable pseudo-terminal allocation
+    -o  Used to give options in the format used in the configuration file (man ssh_config)
+      ServerAliveInterval   Interval in seconds to ping the server while connection has been inactive
+      ExitOnForwardFailure  Whether to terminate the connection if it cannot set up all requested port forwards
+    -R  Forward given remote TCP port (22221) to the local port (22)
+    -v  Verbose mode. More v's increase verbosity.
+```
+the specific unit file to place under: `/etc/systemd/system/ssh-reverse.service`
+
+
+```
+    [Unit]
+    Description=Reverse SSH connection
+    After=network.target
+    
+    [Service]
+    Type=simple
+    ExecStart=/usr/bin/ssh -vvv -g -N -T -o "ServerAliveInterval 10" -o "ExitOnForwardFailure yes" -R 22221:localhost:22 {target_IP}
+    Restart=always
+    RestartSec=5s
+    
+    [Install]
+    WantedBy=default.target
+    
+```
+ 
+ credits belongs to blog.stigok.com

systemd-bootdelay.md

@@ -1,18 +1,19 @@
+# systemd cheat sheet
 ## systemd- bootdelay analyzing
-Short summarize over boot duration
-	system-analyze
-Generate plot for systemd boot process
-	system-analyze plot > boot.svg
-	firefox boot.svg
-kernel log with delta in time
-	dmesg --show-delta --color=always | less -R
-correlate initramfs with kernel messages
-	journalctl -b -o short-monotonic
-sort systemd load times
-	systemd-analyze blame
-select specific initramfs service
-	journalctl -b -o short-monotonic -u systemd-udev-settle.service
-analyse with systemd-bootchart
-	init=/lib/systemd/systemd-bootchart
-the chart file is located under /run/log/bootchart
+- Short summarize over boot duration
+	`system-analyze`
+- Generate plot for systemd boot process
+	`system-analyze plot > boot.svg`
+	`firefox boot.svg`
+- kernel log with delta in time
+	`dmesg --show-delta --color=always | less -R`
+-correlate initramfs with kernel messages
+	`journalctl -b -o short-monotonic`
+- sort systemd load times
+	`systemd-analyze blame`
+-select specific initramfs service
+	`journalctl -b -o short-monotonic -u systemd-udev-settle.service`
+- analyse with systemd-bootchart
+	`init=/lib/systemd/systemd-bootchart`
+- the chart file is located under `/run/log/bootchart`