Alpine BackupPC 4 With Nginx

☰ Table of Content

Deploying BackupPC 4.x on Alpine require some efforts.

BackupPC 4.X

BackupPC is a Linux base backup software with a web frontend. It support client across Linux, Windows, MacOS and other UNIX-base system.

Dev Dependencies

We will install all the dependencies for rsync-bpc, BackupPC-XS and BackupPC 4.x.

Following can be removed after the build process.

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apk add \
  acl-dev \
  attr-dev \
  build-base \
  expat-dev \
  git \
  gnu-libiconv-dev \
  perl-dev \
  popt-dev \
  samba-dev \
  zlib-dev

Following will be kept after building BackupPC.

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apk add \
  acl \
  apache-utils \       # For htpasswd
  expat \
  fcgiwrap \
  nginx \
  openssh-client \
  perl \
  perl-archive-zip \
  perl-cgi \
  perl-encode-utils \
  perl-file-listing \
  perl-xml-rss \
  popt \
  rrdtool \
  rsync \
  samber-client \      # For Windows backup
  zlib

Create User

Create user backuppc.

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adduser backuppc

Compiling & Install

BackupPC github page list out 2 dependency packages.

rsync-bpc

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git clone https://github.com/backuppc/rsync-bpc.git
cd rsync-bpc
./configure
make install

BackupPC-XS

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git clone https://github.com/backuppc/backuppc-xs.git
cd backuppc-xs
perl Makefile.PL
make install

BackupPC

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wget https://github.com/backuppc/backuppc/releases/download/4.3.1/BackupPC-4.3.1.tar.gz
cd BackupPC-4.3.1
perl configure.pl

Note: Following are settings I choose that will affect configuration files in later part.

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$Conf{TopDir}      = '/home/backuppc/data';
$Conf{RunDir}      = '/home/backuppc';
$Conf{InstallDir}  = '/home/backuppc';
$Conf{CgiDir}      = '/home/backuppc/cgi-bin';
$Conf{CgiImageDir} = '/home/backuppc/img';
$Conf{CgiImageDirURL} = '/img';

Clean Up

You can keep the build dependencies or remove them.

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  apk del \
    acl-dev \
    attr-dev \
    build-base \
    expat-dev \
    git \
    gnu-libiconv-dev \
    perl-dev \
    popt-dev \
    samba-dev \
    zlib-dev

Nginx Configuration

Note: Check and modify according to what is in your config.pl.

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server {
  listen 80;
  listen [::]:80;
  server_name a64-hp-01;

  access_log /var/log/nginx/backuppc.access_log;
  error_log  /var/log/nginx/backuppc.error_log;


  location / {
    auth_basic "BackupPC admin";
    auth_basic_user_file /etc/BackupPC/htpasswd;
    alias /home/backuppc/cgi-bin/;
    return 302 http://a64-hp-01/BackupPC_Admin;
  }

  location /img {
    alias /home/backuppc/img;
  }

  location ~ ^/BackupPC_Admin(/|$) {
    gzip off;
    include /etc/nginx/fastcgi_params;
    fastcgi_pass unix:/run/fcgiwrap/fcgiwrap.sock;
    fastcgi_param REMOTE_ADDR     $remote_addr;
    fastcgi_param REMOTE_USER     $remote_user;
    fastcgi_param SCRIPT_FILENAME /home/backuppc/cgi-bin/BackupPC_Admin;
  }
}

Startup Scripts

/etc/init.d/fcgiwrap

fcgiwrap’s socket is not group writable. I cannot get around it even with filesystem ACL setting default group write permission for /run/fcgiwrap/.

One solution is to run Nginx as user backuppc. However that make nginx almost exclusively for BackupPC.

The other solution is use chmod after the socket is created. I modified /etc/init.d/fcgiwrap to do exactly just that.

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#!/sbin/openrc-run

name="fcgiwrap"
description="fcgiwrap cgi daemon"

command="/usr/bin/fcgiwrap"
command_background="yes"
user="backuppc"
group="nginx"
: ${socket:=unix:/run/fcgiwrap/fcgiwrap.sock}

depend() {
  need net localmount
  after firewall
}

start_pre() {
  command_args="-c ${nproc:-$(nproc)} -s $socket"
  case "$socket" in
  unix:/*)
    local socket_path=${socket#unix:}
    checkpath --directory --mode 2775 --owner ${user}:${group} \
      ${socket_path%/*}
    ;;
  esac
}

start_fcgiwrap() {
  start-stop-daemon --exec ${command} \
    --background \
    -u ${user} -g ${group} \
    --start -- ${command_args}
}

start_chmod() {
  chmod g+w /run/fcgiwrap/fcgiwrap.sock
}

stop_post() {
case "$socket" in
unix:/*)
  rm -f "${socket#unix:}"
  ;;
esac
}

start() {
for i in fcgiwrap chmod
do
  ebegin "Starting $i"
  start_$i
  eend $?
done
}

/etc/init.d/backuppc

As BackupPC configuration.pl only comes with systemd service file, we will use Alpine BackupPC 3.x startup script and modify accordingly.

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#!/sbin/openrc-run

extra_started_commands="reload"

: ${user:="backuppc"}
: ${logdir:="/var/log/BackupPC"}
: ${command_args:="-d"}

command="/home/backuppc/bin/BackupPC"
start_stop_daemon_args="--interpreted --user $user"
pidfile="/home/backuppc/BackupPC.pid"
retry="30"

depend() {
  after firewall modules
}

start_pre() {
  checkpath -d -o $user -m 755 "${pidfile%/*}"
}

reload() {
  ebegin "Reloading $name"
  start-stop-daemon --signal 1 --pidfile "$pidfile" -x /usr/bin/perl
  eend $?
}

Conclusion

This should give a very good starting point of running BackupPC 4.x with Nginx on Alpine.

Reference

freebsd + nginx + backuppc

John Siu

Update: 2022-05-12

Tag

[alpine-linux]

[backuppc]

[how-to]

[nginx]

John Siu Blog