3

I'm running raspbian on RPi3 and I've installed and configured nginx to proxy to two different applications running on different ports:

server {
listen 80 default_server;

root /var/www/html;

index index.html index.htm index.nginx-debian.html index.php;

server_name _;

location /first/ {
    proxy_pass http://localhost:8081;
    proxy_set_header Host localhost:8081;
    proxy_redirect default;
}

location /second/ {
    proxy_pass http://localhost:9091;
}

location / {
    try_files $uri $uri/ =404;
}
}

However, whenever I reboot the Pi, nginx seems to somehow load wrongly. It doesn't fail and I can access the static pages on root. However the apps running on /first/ and /second/ location just don't work properly (since their resources like js and css don't load). In the error.log I can see:

2016/04/17 11:24:04 [alert] 1777#0: *86 socket() failed (97: Address family not supported by protocol) while connecting to upstream, client: 192.168.1.237, server: _, request: "GET /first/home/ HTTP/1.1", upstream: "http://[::1]:8081/first/home/", host: "raspberry"

If I then do a simple sudo service nginx reload all is fine again.

My guess is that somehow, during boot, nginx loads too early and doesn't have all that's needed to work properly. However, didn't manage to figure out what would that be and how to fix it.

Any help appreciated.

EDIT: init script added

Here is the init script that's used to load the nginx. It should be the standard one as I have not made any changes to it.

#!/bin/sh

### BEGIN INIT INFO
# Provides:   nginx
# Required-Start:    $local_fs $remote_fs $network $syslog $named
# Required-Stop:     $local_fs $remote_fs $network $syslog $named
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: starts the nginx web server
# Description:       starts nginx using start-stop-daemon
### END INIT INFO

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DAEMON=/usr/sbin/nginx
NAME=nginx
DESC=nginx

# Include nginx defaults if available
if [ -r /etc/default/nginx ]; then
    . /etc/default/nginx
fi

STOP_SCHEDULE="${STOP_SCHEDULE:-QUIT/5/TERM/5/KILL/5}"

test -x $DAEMON || exit 0

. /lib/init/vars.sh
. /lib/lsb/init-functions

# Try to extract nginx pidfile
PID=$(cat /etc/nginx/nginx.conf | grep -Ev '^\s*#' | awk 'BEGIN { RS="[;{}]" } { if ($1 == "pid") print $2 }' | head -n1)
if [ -z "$PID" ]
then
    PID=/run/nginx.pid
fi

# Check if the ULIMIT is set in /etc/default/nginx
if [ -n "$ULIMIT" ]; then
    # Set the ulimits
    ulimit $ULIMIT
fi

#
# Function that starts the daemon/service
#
do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    start-stop-daemon --start --quiet --pidfile $PID --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PID --exec $DAEMON -- \
        $DAEMON_OPTS 2>/dev/null \
        || return 2
}

test_nginx_config() {
    $DAEMON -t $DAEMON_OPTS >/dev/null 2>&1
}

#
# Function that stops the daemon/service
#
do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    start-stop-daemon --stop --quiet --retry=$STOP_SCHEDULE --pidfile $PID --name $NAME
    RETVAL="$?"

    sleep 1
    return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
    start-stop-daemon --stop --signal HUP --quiet --pidfile $PID --name $NAME
    return 0
}

#
# Rotate log files
#
do_rotate() {
    start-stop-daemon --stop --signal USR1 --quiet --pidfile $PID --name $NAME
    return 0
}

#
# Online upgrade nginx executable
#
# "Upgrading Executable on the Fly"
# http://nginx.org/en/docs/control.html
#
do_upgrade() {
    # Return
    #   0 if nginx has been successfully upgraded
    #   1 if nginx is not running
    #   2 if the pid files were not created on time
    #   3 if the old master could not be killed
    if start-stop-daemon --stop --signal USR2 --quiet --pidfile $PID --name $NAME; then
        # Wait for both old and new master to write their pid file
        while [ ! -s "${PID}.oldbin" ] || [ ! -s "${PID}" ]; do
            cnt=`expr $cnt + 1`
            if [ $cnt -gt 10 ]; then
                return 2
            fi
            sleep 1
        done
        # Everything is ready, gracefully stop the old master
        if start-stop-daemon --stop --signal QUIT --quiet --pidfile "${PID}.oldbin" --name $NAME; then
            return 0
        else
            return 3
        fi
    else
        return 1
    fi
}

case "$1" in
    start)
        [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
        do_start
        case "$?" in
            0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
            2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
    stop)
        [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
        do_stop
        case "$?" in
            0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
            2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
    restart)
        log_daemon_msg "Restarting $DESC" "$NAME"

        # Check configuration before stopping nginx
        if ! test_nginx_config; then
            log_end_msg 1 # Configuration error
            exit 0
        fi

        do_stop
        case "$?" in
            0|1)
                do_start
                case "$?" in
                    0) log_end_msg 0 ;;
                    1) log_end_msg 1 ;; # Old process is still running
                    *) log_end_msg 1 ;; # Failed to start
                esac
                ;;
            *)
                # Failed to stop
                log_end_msg 1
                ;;
        esac
        ;;
    reload|force-reload)
        log_daemon_msg "Reloading $DESC configuration" "$NAME"

        # Check configuration before reload nginx
        #
        # This is not entirely correct since the on-disk nginx binary
        # may differ from the in-memory one, but that's not common.
        # We prefer to check the configuration and return an error
        # to the administrator.
        if ! test_nginx_config; then
            log_end_msg 1 # Configuration error
            exit 0
        fi

        do_reload
        log_end_msg $?
        ;;
    configtest|testconfig)
        log_daemon_msg "Testing $DESC configuration"
        test_nginx_config
        log_end_msg $?
        ;;
    status)
        status_of_proc -p $PID "$DAEMON" "$NAME" && exit 0 || exit $?
        ;;
    upgrade)
        log_daemon_msg "Upgrading binary" "$NAME"
        do_upgrade
        log_end_msg 0
        ;;
    rotate)
        log_daemon_msg "Re-opening $DESC log files" "$NAME"
        do_rotate
        log_end_msg $?
        ;;
    *)
        echo "Usage: $NAME {start|stop|restart|reload|force-reload|status|configtest|rotate|upgrade}" >&2
        exit 3
        ;;
esac

:
  • Could you show the file which your init system uses to start nginx? – gf_ Apr 17 '16 at 12:15
2

Could be a problem related to localhost being called by its IPv6("::1") as stated in the cited alert:

 request: "GET /first/home/ HTTP/1.1", upstream: "http://[::1]:8081/first/home/"

Try to replace "localhost" by "127.0.0.1" in your proxy configuration.

  • This indeed has helped. Thanks. Any idea why this issue disappears after reload? – Filip Kis Apr 18 '16 at 17:57
  • Nope. I don't know when during boot etc/hosts gets read. Maybe it has to do with that, but that's just a very vague idea. – JosefScript Apr 18 '16 at 18:24
  • Another vague idea. Avahi maybe. debian.org/doc/manuals/debian-reference/… – JosefScript Apr 18 '16 at 19:23

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