Configure Jenkin slave

setup_slave.sh

#!/bin/sh

main() {
  configure_ssh_known_hosts
  configure_mysql_ram_disk
  configure_idle_tracking
}

configure_ssh_known_hosts() {
  echo configuring ssh known hosts
  
  # Fetch github's SSH host information and add it to known_hosts to
  # prevent git clone from asking whether it is valid or not
  ssh-keyscan -t rsa github.com >> $HOME/.ssh/known_hosts
  
  # Also add github.com's ip address because it seems to be breaking otherwise
  ssh-keyscan -t rsa $(dig +short A github.com) >> $HOME/.ssh/known_hosts
  
  # Hard-code this IP documented by github. We haven't experienced a failure as a result of this, but just in case...
  # https://help.github.com/articles/error-permission-denied-publickey#check-that-you-are-connecting-to-the-correct-server
  ssh-keyscan -t rsa 207.97.227.239 >> $HOME/.ssh/known_hosts
  
  chmod 600 $HOME/.ssh/known_hosts
  chown ubuntu.ubuntu $HOME/.ssh/known_hosts
}

configure_mysql_ram_disk() {
  echo configuring mysql ram disk
  sudo service mysql stop;
  sudo cp -pRL /var/lib/mysql /dev/shm/mysql;
  
  sudo cat > /etc/mysql/conf.d/ramdisk.cnf << EOF
[mysqld]
datadir = /dev/shm/mysql
EOF

  sudo service mysql start;
}

configure_idle_tracking() {
  echo configuring idle tracking
  mkdir -p /tmp/idle-tracking
  chmod 777 /tmp/idle-tracking
}

main