frr/doc/Building_FRR_on_CentOS7.md

Building FRR on CentOS 7 from Git Source
========================================

CentOS 7 restrictions:
----------------------

- MPLS is not supported on `CentOS 7` with default kernel. MPLS requires 
  Linux Kernel 4.5 or higher (LDP can be built, but may have limited use 
  without MPLS)
  
Install required packages
-------------------------
		
Add packages:

	sudo yum install git autoconf automake libtool make gawk readline-devel \
	  texinfo net-snmp-devel groff pkgconfig json-c-devel pam-devel \
	  bison flex pytest

Get FRR, compile it and install it (from Git)
---------------------------------------------

**This assumes you want to build and install FRR from source and not using any packages**

### Add frr groups and user

	sudo groupadd -g 92 frr
	sudo groupadd -r -g 85 frrvt
	sudo useradd -u 92 -g 92 -M -r -G frrvt -s /sbin/nologin \
	  -c "FRR FreeRangeRouting suite" -d /var/run/frr frr

### Download Source, configure and compile it
(You may prefer different options on configure statement. These are just an example.)

You may want to pay special attention to `/usr/lib64` paths and change them if you are not building on a x86_64 architecture

	git clone https://github.com/freerangerouting/frr.git frr
	cd frr
	git checkout stable/2.0
	./bootstrap.sh
	./configure \
    	--sysconfdir=/etc/frr \
    	--libdir=/usr/lib64/frr \
    	--libexecdir=/usr/lib64/frr \
    	--localstatedir=/var/run/frr \
    	--enable-snmp=agentx \
    	--enable-multipath=64 \
    	--enable-ospfclient=yes \
    	--enable-ospfapi=yes \
    	--enable-user=frr \
    	--enable-group=frr \
    	--enable-vty-group=frrvt \
    	--enable-rtadv \
    	--disable-exampledir \
    	--enable-watchfrr \
    	--enable-tcp-zebra \
    	--enable-fpm \
    	--with-pkg-git-version \
    	--with-pkg-extra-version=-MyOwnFRRVersion	
	make
	make check
	sudo make install

### Create empty FRR configuration files
	sudo mkdir /var/log/frr
	sudo mkdir /etc/frr
	sudo touch /etc/frr/zebra.conf
	sudo touch /etc/frr/bgpd.conf
	sudo touch /etc/frr/ospfd.conf
	sudo touch /etc/frr/ospf6d.conf
	sudo touch /etc/frr/isisd.conf
	sudo touch /etc/frr/ripd.conf
	sudo touch /etc/frr/ripngd.conf
	sudo touch /etc/frr/pimd.conf
	sudo chown -R frr:frr /etc/frr/
	sudo touch /etc/frr/vtysh.conf
	sudo chown frr:frrvt /etc/frr/vtysh.conf
	sudo chmod 640 /etc/frr/*.conf

### Enable IP & IPv6 forwarding

Create a new file `/etc/sysctl.d/90-routing-sysctl.conf` with the following content:

    # Sysctl for routing
    #
    # Routing: We need to forward packets
    net.ipv4.conf.all.forwarding=1
    net.ipv6.conf.all.forwarding=1

**Reboot** or use `sysctl` to apply the same config to the running system

### Install Service files 
	sudo install -p -m 644 redhat/zebra.service /usr/lib/systemd/system/zebra.service
	sudo install -p -m 644 redhat/isisd.service /usr/lib/systemd/system/isisd.service
	sudo install -p -m 644 redhat/ripd.service /usr/lib/systemd/system/ripd.service
	sudo install -p -m 644 redhat/ospfd.service /usr/lib/systemd/system/ospfd.service
	sudo install -p -m 644 redhat/bgpd.service /usr/lib/systemd/system/bgpd.service
	sudo install -p -m 644 redhat/ospf6d.service /usr/lib/systemd/system/ospf6d.service
	sudo install -p -m 644 redhat/ripngd.service /usr/lib/systemd/system/ripngd.service
	sudo install -p -m 644 redhat/pimd.service /usr/lib/systemd/system/pimd.service
	sudo install -p -m 644 redhat/frr.sysconfig /etc/sysconfig/frr
	sudo install -p -m 644 redhat/frr.logrotate /etc/logrotate.d/frr

### Register the systemd files
	sudo systemctl preset zebra.service
	sudo systemctl preset ripd.service
	sudo systemctl preset ospfd.service
	sudo systemctl preset bgpd.service
	sudo systemctl preset ospf6d.service
	sudo systemctl preset ripngd.service
	sudo systemctl preset pimd.service

### Enable required daemons at startup
Only enable zebra and the daemons which are needed for your setup

	sudo systemctl enable zebra
	sudo systemctl enable ospfd
	sudo systemctl enable bgpd
	[...] etc (as needed)