Kernel needs ============== Compile a kernel with the following options : Kernel/User netlink socket LinuxVirtualServer Keepalived supports all LVS code. Library dependencies ==================== In order to compile Keepalived needs the following libraries : * OpenSSL, Linux flavours ============== RedHat based systems (RedHat Enterprise/CentOS/Fedora) ------------------------------------------------------ The following build packages are needed: make autoconf automake (to build from git source tree rather than tarball) The following libraries need to be installed: openssl-devel libnl3-devel ipset-devel For iptables support: libxtables-dev libip6tc-dev libip4tc-dev or on older installations: iptables-devel For magic file identification support: file-devel For SNMP support: net-snmp-devel For DBUS support: glib2-devel For PCRE support pcre2-devel For nftables support libnftnl-devel libmnl-devel For building the documentation, the following packages need to be installed: Fedora: python-sphinx (will pull in: python2-sphinx_rtd_theme) CentOS-and-friends: python-sphinx epel-release python-sphinx_rtd_theme For latex or pdf files, the following are also needed: Fedora: latexmk python-sphinx-latex CentOS-and-friends: latexmk texlive texlive-titlesec texlive-framed texlive-threeparttable texlive-wrapfig texlive-multirow Debian/Ubuntu ------------- For building packages: build-essential pkg-config, and to build from git repo automake autoconf The following libraries need to be installed: iptables-dev libipset-dev libnl-3-dev libnl-genl-3-dev libssl-dev For magic file identification support: libmagic-dev For SNMP support: libsnmp-dev For DBUS support: libglib2.0-dev For PCRE support: libpcre2-dev For nftables support libnftnl-dev libmnl-dev For building the documentation, the following packages need to be installed: python-sphinx python-sphinx-rtd-theme For latex or pdf files, the following are also needed: texlive-latex-base texlive-generic-extra texlive-latex-recommended texlive-fonts-recommended texlive-latex-extra Alpine Linux ------------ The following libraries need to be installed: iptables-dev ipset-dev libnl3-dev musl-dev libnftnl-dev and openssl-dev or libressl-dev For magic file identification support: file-dev For SNMP support: net-snmp-dev (requires libressl-dev and not openssl-dev) For PCRE support pcre2-dev For building the documentation, the following packages need to be installed: py-sphinx py3-sphinx_rtd_theme For latex or pdf files, you'll need texlive or similar, which is not yet available as a distro package. Archlinux --------- Run the following to install the required libraries: pacman -S ipset libnl1 For magic file identification support: TDB For SNMP support: pacman -S net-snmp for PCRE support: pcre-2 (may be installed by default) For building the documentation, the following packages need to be installed: python-sphinx python-sphinx_rtd_theme For latex or pdf files, the following are also needed: texlive-core texlive-bin texlive-latexextra Kernel configuration requirements --------------------------------- The following list is probably incomplete, and will be updated as other options become known. BPF EPOLL SIGNALFD TIMERFD SYSCTL PROC_FS INET IP_MULTICAST IPV6 IP_VS (unless --disable-lvs is specified) IP_VS suboptions to match the real_server/virtual_server configuration NETFILTER_XTABLES - if strict_mode or no_accept. NETFILTER_XT options and IP_SET NF_TABLES and associated components - to use nftables for strict_mode or no_accept IP_ADVANCED_ROUTER and various associated options if static/dynamic routes specified FIB_RULES if static or dynamic rules are specified Installing from a git repo ========================== To install from a git repo, execute: 1. Ensure you have autoconf and automake installed 2. git clone http://github.com/acassen/keepalived 3. cd keepalived 4. ./build_setup # generate the autoconf and automake environment 5. Follow the instructions below for Installation, omitting the first two steps. Installation ============ 1. tar -xf TARFILE 2. cd into the directory 3. './configure' 4. 'make' 5. 'make install'. This will install keepalived on your system, binaries and configuration file : * keepalived : The keepalived daemon program. * genhash : The MD5 url digest generator. You need it to configure HTTP GET check and SSL GET check in order to compute MD5SUM digest etalon. * /etc/keepalived/keepalived.conf 6. link keepalived.init into your runlevel directory. On Red Hat systems : ln -s /etc/rc.d/init.d/keepalived.init /etc/rc.d/rc3.d/S99keepalived By default the configure script uses /usr/local as base directory. You can change this value to your own by passing it the --prefix value. eg: './configure --prefix=/usr/' Building RPM files ================== If building from tarball: 1a. tar -xf TARFILE 1b. cd into the directory If building from git clone: 1. ./build_setup For tarball and git 2. ./configure 3. make rpm The .rpm files will be created in directory `rpm --eval "%{_rpmdir}"`/ARCH Modifying source code ===================== If you modify the source code, especially configure.ac or any Makefile.am file, you will need to regenerate the build files. Keepalived uses automake and so you will need to have automake and autoconf installed. Configuration ============= Just take a look at the /etc/keepalived/keepalived.conf file installed. It will give you all the information needed. Alternativley, run 'man keepalived.conf' or look at doc/keepalived.conf.SYNOPSIS. If you want more information about keepalived, please refer to the keepalived homepage into the documentation section. http://www.keepalived.org Creating a docker container =========================== There is a very useful github project maintained by osixia for building a docker container with keepalived. To use, run the following: git clone https://github.com/osixia/docker-keepalived.git cd docker-keepalived make build docker run --name keepalived --cap-add=NET_ADMIN --net=host \ --env KEEPALIVED_INTERFACE=eth0 -d osixia/keepalived:1.3.5 \ # or whatever version of keepalived you have To update the keepalived source code, put a new tarball in the image directory (the Dockerfile may need updating with a new version). Useful docker commands are: docker logs keepalvied 2>&1 | lessa # view system logs of container docker exec it keepalived bash # execute shell in container docker rm -f keepalived # Remove the container keepalived is unable to load the ip_tables, ip6_tables, xt_set and ip_vs modules from within the container, so ensure they are already loaded in the host system. To generate a core file in the root filesystem of the container, /proc/sys/kernel/core_pattern needs to be updated in the host system, and not from the container (or in other words the -M option to keepalived does not work within a container. Installing gdb in the container (edit the image/Dockerfile to add it before make build) may be helpful if you need to examine core files in the container. Running in an AWS container =========================== The VRRP protocol is not enabled in AWS security groups. If you are using AWS, create a rule in the AWS security group. The rule should be "Custom Protocol" and value should be "112" (the VRRP protocol number). All ports should be opened. Running with SElinux ==================== If the system running keepalived has SElinux enabled in enforcing mode, keepalived may have difficulty running scripts, accessing configuration files, etc, especially if keepalived is being started by systemd. By default, scripts should be located in /usr/libexec/keepalived, or alternatively, to set the necessary security context for a script, execute: chcon -t keepalived_unconfined_script_exec_t PATH_TO_SCRIPT See https://www.mankier.com/8/keepalived_selinux and https://www.mankier.com/8/keepalived_unconfined_script_selinux for further details of SElinux and keepalived. Have fun with it ! Alexandre,