Added network space information and example.

Minor changes to text to make .md linter happy

README.md

@@ -1,25 +1,24 @@
 # Overview
 
 Magpie is a charm used for testing the networking of a juju provider/substrate.
-Simply deploy more than one Magpie charm and watch the status messages and
-debug logs. 
+Simply deploy Magpie charm to at least two units and watch the status messages and
+debug logs.
 
 Magpie will test:
 
- - DNS functionality
- - Local hostname lookup
- - ICMP between peers
- - MTU between leader and clients
- - Transfer between leader and clients
+- DNS functionality
+- Local hostname lookup
+- ICMP between peers
+- MTU between leader and clients
+- Transfer between leader and clients
 
-*MTU and transfer speed are tested with iperf2*
+Note : **MTU and transfer speed are tested with iperf2**
 
-Status messages will show the unit numbers that have issues - if there are 
+Status messages will show the unit numbers that have issues - if there are
 no problems, there will not be a verbose status message.
 
 All actions, strings, queries and actions are logged in the juju logs.
 
-
 # MTU Notes
 
 The MTU size reported by iperf is sometimes 8 or 12 bytes less than the configured
@@ -30,17 +29,14 @@ and therefore we ignore that difference and report everything OK.
 
 In addition to ICMP and DNS status messages, if a networking problem is
 detected, the workload status of the agent which has found the issues
-will be set to blocked. 
-
+will be set to blocked.
 
 # Reactive States
 
 This layer will set the following states:
 
-* **`magpie-icmp.failed`** ICMP has failed to one or more units in the peer
-relation.
-* **`magpie-dns.failed`** DNS has failed to one or more units in the peer 
-relation.
+- **`magpie-icmp.failed`** ICMP has failed to one or more units in the peer relation.
+- **`magpie-dns.failed`** DNS has failed to one or more units in the peer relation.
 
 Note: work stopped on these states as it is currently unlikely magpie will be consumed
 as a layer.
@@ -48,7 +44,7 @@ Please open an issue against this github repo if more states are required.
 
 # Usage
 
-```
+``` code
 juju deploy magpie -n 2
 juju deploy magpie -n 1 --to lxd:1
 ```
@@ -83,17 +79,37 @@ This charm also supports the following config values:
   required_mtu:
     default: 0
     description: |
-        Desired MTU for all nodes - block if the unit MTU is different 
+        Desired MTU for all nodes - block if the unit MTU is different
         (accounting for encapsulation). 0 disables.
     type: int
   min_speed:
     default: 0
     description: |
-        Minimum transfer speed in mbits/s required to pass the test. 
+        Minimum transfer speed in mbits/s required to pass the test.
         0 disables.
 ```
 
 e.g.
 
+``` code
 juju set magpie dns_server=8.8.8.8 required_mtu=9000 min_speed=1000
+```
 
+## Network spaces
+
+If you use network spaces in your Juju deployment (as you should) use
+`--bind '<space-name> magpie=<space-name>'` to force magpie to test that
+particular network space.
+
+It is possible to deploy several magpie charms
+(as different Juju applications) to the same server each in a different
+network space.
+
+Example:
+
+``` code
+juju deploy -m magpie cs:~admcleod/magpie magpie-space1 --bind "space1 magpie=space1" -n 5 --to 0,2,1,4,3
+juju deploy -m magpie cs:~admcleod/magpie magpie-space2 --bind "space2 magpie=space2" -n 3 --to 3,2,0
+juju deploy -m magpie cs:~admcleod/magpie magpie-space3 --bind "space3 magpie=space3" -n 4 --to 3,2,1,0
+juju deploy -m magpie cs:~admcleod/magpie magpie-space4 --bind "space4 magpie=space4" -n 4 --to 3,2,1,0
+```