Re: CentOS 7 and keepalived

Hi,

Thank you Pim.  Seems to be working now.  Although I've yet to find any 
one document that advocates everything you specified below.  What I had 
running in my original post worked  fine under 6.4 I think it was.  I've 
configured all of it into my cobbler and puppet servers and can get them 
to install and configure both sides of the system now.

Only remaining issue has nothing to do with keepalived.  It's the 
VirtualBox software.  In certain cases things don't work right between 
hosts but work fine if all VMs are on one host.  Possible packet filter 
issue.  I'll have to ask on the VBox list.

But thank you people.

Chris.

> Hi Chris,
>
>
> The RHEL 6 load balancing manual contains extensive documentation for setting up LVS-DR. The RHEL 7 manual does not contain similar documentation regarding LVS-DR (layer 4 load balancing), because they now prefer you use HAproxy (layer 7 load balancing). However, LVS-DR should still work the same on CentOS 7.
>
> I am not aware of the current recommendations regarding the tricks you tried in sysctl (I don't use any of the changes you posted!) and your network setup using an alias on the loopback interface. I have always followed these steps (taken from my internal documentation, based on the RHEL and LVS manuals):
>
> Setup a virtual IP address on a real server (for use in an LVS-DR setup):
>
> 1. Install arptables
>
> # CentOS 6
> yum install arptables_jf
>   
> # CentOS 7
> yum install arptables
>
> 2. Configure arptables
>
> # CentOS 6
> arptables -A IN -d <virtual_ip> -j DROP
> arptables -A OUT -s <virtual_ip> -j mangle --mangle-ip-s <real_ip>
>
> # CentOS 7
> arptables -A INPUT -d <virtual_ip> -j DROP
> arptables -A OUTPUT -s <virtual_ip> -j mangle --mangle-ip-s <real_ip>
>
> 3. Save arptables configuration (overwrites any existing configuration)
>
> # CentOS 6
> service arptables_jf save
>   
> # CentOS 7
> arptables-save > /etc/sysconfig/arptables
>
> 4. Enable arptables service
>
> # CentOS 6
> chkconfig arptables_jf on
>   
> # CentOS 7
> systemctl enable arptables.service
>
> 5. After that you can add the virtual IP address. You need to make the netwerk configuration persistent for reboots.
>
> ip addr add <virtual_ip>/<cidr> dev <device name e.g. eth0>
>
> Good luck!
>
> - Pim
>
>
>


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