Keepalived运行状况检查无法连接到127.0.0.1

Question

I've currently got a cluster of servers running Centos 7 and Docker, and I want to use Keepalived to allocate a floating IP between them. I've configured Keepalived to run a check command on each node which just does curl --silent --fail localhost:80 to ensure a HTTP server is listening.

The web app is running using a Docker container bound to port 80 and --net=host on Docker 1.10.3. Firewalld is also completely disabled.

The problem I'm having is that the curl never succeeds. If I change the check command to echo '' or anything else which exits 0 (without any network interaction) it works fine, but for some reason the curl doesn't work. When I run it from a normal bash terminal it is fine, and echo $? prints a 0.

I'm not even sure how to debug this as Keepalived doesn't provide any documentation on the matter and doesn't seem to log anything in relation to errors coming from the vrrp script.

Any help or suggestions would be greatly appreciated.

Answer 1

Turns out I was using an ancient version of Keepalived. Compiling the latest version from source fixed the issue (rather than using the binary from Centos repos)