Azkaban web server init.d script

azkaban-web

#!/bin/bash
#
# azkaban-web   Start Up Azkaban web server
#
# chkconfig: 2345 95 5
# description: Azkaban allows users to run queries on EMR (Hadoop) clusters \
#              via a web interface

### BEGIN INIT INFO
# Provides: azkaban
# Required-Start: $network $local_fs $remote_fs $syslog
# Required-Stop: $network $local_fs $remote_fs
# Should-Start: $syslog $named
# Should-Stop: $syslog $named
# Short-Description: start and stop Azkaban Web Server
# Description: Azkaban allows users to run queries on EMR (Hadoop) clusters \
#              via a web interface
### END INIT INFO

# TODO: would be nice if status messages would be right-aligned and colored

# Source function library.
. /etc/init.d/functions

# Source networking configuration.
. /etc/sysconfig/network

prog=azkaban-web
azkaban_dir="/opt/azkaban-web"
config_dir="{{ azkaban_dir }}/conf/"
logs_dir="/var/log/azkaban-web"
tmpdir="/tmp"
pid_file="/var/run/azkaban-web.pid"

start() {
    [ "$EUID" != "0" ] && exit 4
    [ "$NETWORKING" = "no" ] && exit 1
    [ -d "$config_dir" ] || exit 5
    #. /etc/sysconfig/azkaban-web

    RETVAL=0
    PATH=$azkaban_dir:$PATH # probably not necessary
    # add all azkaban jar files to CLASSPATH
    for file in $azkaban_dir/lib/*.jar;
    do
        CLASSPATH=$CLASSPATH:$file
    done
    for file in $azkaban_dir/extlib/*.jar;
    do
        CLASSPATH=$CLASSPATH:$file
    done
    for file in $azkaban_dir/plugins/*/*.jar;
    do
        CLASSPATH=$CLASSPATH:$file
    done
    if [ "$HADOOP_HOME" != "" ]; then
        CLASSPATH=$CLASSPATH:$HADOOP_HOME/conf:$HADOOP_HOME/*
        JAVA_LIB_PATH="-Djava.library.path=$HADOOP_HOME/lib/native/Linux-amd64-64"
    else
        logger -s "azkaban-web init.d: HADOOP_HOME is not set. Hadoop job types will not run properly."
    fi
    if [ "$HIVE_HOME" != "" ]; then
        CLASSPATH=$CLASSPATH:$HIVE_HOME/conf:$HIVE_HOME/lib/*
    fi
    executorport=`cat $azkaban_dir/conf/azkaban.properties | grep executor.port | cut -d = -f 2`
    serverpath=$azkaban_dir
    if [ -z "$AZKABAN_OPTS" ]; then
        AZKABAN_OPTS="-Xmx3G"
    fi
    AZKABAN_OPTS="$AZKABAN_OPTS -server -Dcom.sun.management.jmxremote -Djava.io.tmpdir=$tmpdir -Dexecutorport=$executorport -Dserverpath=$serverpath -Dlog4j.log.dir=$logs_dir"

    echo -n "Starting azkaban-web: "
    # check if there's already a process up. blissfully ignores pid file
    ps auxww | grep "[a]zkaban\.webapp\.AzkabanWebServer" > /dev/null
    if [ "$?" -eq 0 ]; then
        # already started should be considered success
        # but we avoid starting a second one
        echo "[OK]"
        return 0
    fi
    # start azkaban
    java $AZKABAN_OPTS $JAVA_LIB_PATH -cp $CLASSPATH \
        azkaban.webapp.AzkabanWebServer -conf $azkaban_dir/conf $@ &
    sleep 2
    running_pid=`ps auxww | grep "[a]zkaban\.webapp\.AzkabanWebServer" | head -1 | awk '{print $2}'`
    if [ -z "$running_pid" ]; then
        echo "[FAILED]"
        return 7
    fi
    echo "$running_pid" > $pid_file
    echo "[OK]"
}

stop() {
    echo -n "Stopping azkaban-web: "
    running_pid=`ps auxww | grep "[a]zkaban\.webapp\.AzkabanWebServer" | head -1 | awk '{print $2}'`
    if [ -z "$running_pid" ]; then
        # attempting to stop a process that isn't running should be
        # considered succesful. remove $pid_file if exists
        if [ -f "$pid_file" ]; then
            rm $pid_file
        fi
        echo "[OK]"
        return 0
    fi
    if [ ! -f "$pid_file" ]; then
        # we know that azkaban is running, otherwise it would have been
        # dealt with in the if above
        echo "[FAILED - no PID file, but azkaban running ($running_pid)]"
        return 13
    fi
    pid=`cat $pid_file`
    if [ "$pid" -gt 1 -a "$pid" == "$running_pid" ]; then
        kill $pid
        sleep 1
    fi
    ps auxww | grep "[a]zkaban\.webapp\.AzkabanWebServer" > /dev/null
    if [ "$?" -eq 0 ]; then
        echo "[FAILED]"
        return 13
    fi
    rm $pid_file
    echo "[OK]"
}

status() {
    # check if there's any azkaban process running or a pid file present
    # if neither, then say it's stopped and return proper code
    running_pid=`ps auxww | grep "[a]zkaban\.webapp\.AzkabanWebServer" | head -1 | awk '{print $2}'`
    if [ -z "$running_pid" -a ! -f "$pid_file" ]; then
        echo "azkaban-web is stopped"
        return 3
    fi
    # something is present. check if all good
    if [ ! -f $pid_file ]; then
        echo "azkaban-web (pid $running_pid) is running, but $pid_file doesn't exist"
        return 0
    fi
    pid=`cat $pid_file`
    if [ "$pid" -gt 0 -a "$pid" == "$running_pid" ]; then
        echo "azkaban-web (pid $running_pid) is running..."
        return 0
    fi
    # we got to this point, so something isn't quite right
    if [ -z "$running_pid" ]; then
        # pid_file exists, but azkaban isn't running
        echo "$pid_file exists but there is no azkaban process running"
        return 1
    fi
    if [ -z "$pid" ]; then
        echo "$pid_file contains no PID"
        return 4
    fi
    echo "PID in $pid_file ($pid) is different than running process' PID ($running_pid)"
    return 4
}

# See how we were called.
case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  status)
    status
    ;;
  restart)
    stop
    start
    ;;
  reload)
    stop
    start
    ;;
  *)
    echo $"Usage: $0 {start|stop|status|restart}"
    exit 2
esac

init.d script for Azkaban Web Server. To be used with Linux distributions that didn't move to systemd, like Amazon Linux. Written around the LSB spec (https://refspecs.linuxbase.org/LSB_3.1.0/LSB-generic/LSB-generic/iniscrptact.html), also uses some additional exit codes.

The start() function is pretty much Azkaban's start script with a few changes, like also sending the HADOOP_HOME message to syslog and the maximum java heap to 3GB instead of 4.

stop() will not kill azkaban if the pid_file doesn't exist, even if it finds it running in memory.

Assumes only one Azkaban process running on the system, check how running_pid variable is set.