Deploying Code

Quick Reference

• Static IP: 192.168.2.6
• User: sw8
• Target IP: 192.168.2.5

1: Setting Laptop Environment

Based on ROS connection method

• Install Java 11 through a package manager or direct
• Clone this git repository
• Attach to target single board computer via Ethernet
  • We use a network switch for multiple connections
    • Creates a local network

2: Gradle Deploy

• Prerequisite: Task 1
• Get a copy of ".sw8_ssh_identity"
  • Put it in the "app" directory
  • Ask the software lead for the file
• Get a copy of ".sw8_password"
  • Put it in the "app" directory
  • Text file with the admin password
• Use the deploy task
  • Go to the project root
  • Open in command processor (cmd/bash/zsh/etc)
  • Linux/MacOS: ./gradlew deploy
  • Windows: ./gradlew.bat deploy

3: Direct SSH Access

• Prerequisite: Task 1
• The target address is 192.168.2.5
• Use SSH utility
  • Linux/MacOS: use ssh directly
    • ssh sw8@192.168.2.5
    • For graphics: ssh -x sw8@192.168.2.5
  • Windows: use terminal emulator
    • e.g. MobaXTerm
    • User: sw8
    • Host: 192.168.2.5
    • Port: 22
• Ask for password
• Optional: add "sw8_ssh_identity" to your ssh agent
  • Password not needed if an identity file is provided
  • Ask the software lead for the file

4: Running Code

• Prerequisite: Task 3
• Enter the ~/java directory
  • cd ~/java
• Run app-all.jar
  • java -jar app-all.jar
  • Include flags after the java run
    • java -jar app-all.jar [flags]
    • e.g. java -jar app-all.jar --help

5: tmux

• Online manual page
  • If tmux is installed, can access with "man tmux"
  • Our tmux sessions will be left on all defaults
    • GNU screen users: that means CTRL - b, not CTRL - a
• Purpose of tmux
  • tmux = Terminal Multiplexer
  • Persistent terminal session when connection drops
  • Multiple windows on one connection
  • Generally great tool for terminal work
• Starting tmux To start a new tmux session: "tmux"
  • To connect to a tmux session: "tmux a" or "tmux a [number]"
  • List tmux sessions: "tmux ls"
  • The tmux environment has a green bar at the bottom of the screen
  • Start tmux sessions on the target, not your machine
    • Don't nest tmux sessions
• Basic tmux commands
  • All commands start by typing CTRL - b, then the specific command
  • Create new window: CTRL - b c
  • Close window: CTRL - b &
    • Close pane (works for one pane windows): CTRL - b x
  • Go to window N: CTRL - b N
    • e.g. for window 1, CTRL - b 1
  • Detach: CTRL - b d
    • Reattach with "tmux a"
    • When session is over, do not use detach
      • Use the "exit" command in bash
      • CTRL-d (no CTRL - b first) also exits
  • For more detail, see "DEFAULT KEY BINDINGS" in manual

6: Read-Only Platform Mount

• The system is mounted read-only by default
  • Reduces damage from SD cards degrading on writes
  • Protects against corruption from shutdown during filesystem operations
    • Power loss
    • System crash
    • Filesystems can usually recover, but it's better to not need recovering in the first place
• In order to change files, we need to remount
  • Two aliases provided, require sudo
    • rw
      • remount as read-write (typical filesystem behavior)
    • ro
      • remount as read-only (default machine behavior)

7: Debugging

• Can't connect to target device
  • Make sure user is sw8
    • sw8s is wrong
    • Check password
  • Confirm laptop settings
    • Check against [Task 1](# 1: Setting Laptop Environment)
  • Try ping 192.168.2.5
  • Try a network scan
    • sudo rfkill wlan (IMPORTANT)
      • Disconnects from local WiFi
    • sudo nmap -sn 192.168.2.0/24
      • Scan that doesn't test ports
    • sudo nmap 192.168.2.0/24
      • Scan that tests ports
      • Use if ping/fast scan succeeds but connection fails
  • Confirm next step with leadership
    • Likely power cycling the Pi
• The test phase failed
  • You failed the tests
  • Fix your code or fix the tests
• Can't run java/deployed app
  • Test if java is on the system
    • which java
    • If not, install openjdk11
  • Check default java version
    • java --version
    • If not Java 11, replace with Java 11