Munin & Bind9_rndc

2012/06/18-16:30:03 [28214] Error output from bind9_rndc:
2012/06/18-16:30:03 [28214] rndc: error: none:0: open: /etc/bind/rndc.key: permission denied
2012/06/18-16:30:03 [28214] rndc: could not load rndc configuration

However, via command line (and user root) it works:

/etc/munin/plugins # ./bind9_rndc 
query_recursion.value 0
query_success.value 80
query_nxrrset.value 17
query_requests.value 104
query_failure.value 0
query_duplicates.value 0
query_nonauth_answer.value 0
query_nxdomain.value 4
query_auth_answer.value 101
query_responses.value 104

Solution:

add this to /etc/munin/plugin-conf.d/munin-node:

[bind_rndc]
user bind

and be sure the key has the right ownership:

sudo chown root:bind /etc/bind/rndc.key
sudo chmod 644 /etc/bind/rndc.key

and restart munin-node.