Changes between Version 10 and Version 11 of SystemAdministration/Hosts/beta-vlo-clarin.esc.rzg.mpg.de

Timestamp:

08/31/15 12:10:22 (9 years ago)

Author:

Willem Elbers

Comment:

--

SystemAdministration/Hosts/beta-vlo-clarin.esc.rzg.mpg.de

@@ -38 +38 @@
 
 
-And alternative is using the ip address of the shared docker interface. The docker daemon will create a virtual network interface in the host and one for each container. Each container interface is linked to this host interface and therefore all containers have access to each other via the ip of this host interface. 
+And alternative is using the ip address of the shared docker interface (docker0). The docker daemon will create a virtual network interface in the host and one for each container. Each container interface is linked to this host interface and therefore all containers have access to each other via the ip of this host interface. 
+
+To find the ip address for the shared docker interface, run "ip a | grep docker0:" on the host and look for the ip address.
 
 This approach has the following advantages:
@@ -47 +49 @@
 - Containers must map ports to the host (you can limit this to the shared docker interface and not the public network interface)
 - Each container must expose unique port(s).
+
+If a firewall is running on the host, communication via the docker0 interface might be blocked.
+
+CentOS:
+Check which zones are active:
+{{{
+firewall-cmd --get-active-zones
+}}}
+
+If the docker0 interface is not associated with any zone, run the following to add the docker0 interface to the trusted zone (all communication allowed):
+{{{
+firewall-cmd --permanent --zone=trusted --change-interface=docker0
+sudo firewall-cmd --reload
+}}}
 
 For this setup we use the latter approach.