simplified fabric procedure

tsa/howto/ganeti.mdwn

@@ -218,7 +218,71 @@ hard-recover from a completely crashed node:
 Note that you might need the `--ignore-consistency` flag if the
 node is unresponsive.
 
-## Importing external instances
+## Importing external instances, semi-automatic
+
+Assumptions:
+
+ * `INSTANCE`: name of the instance being migrated, the "old" one
+   being outside the cluster and the "new" one being the one created
+   inside the cluster (e.g. `chiwui.torproject.org`)
+ * `SPARE_NODE`: a ganeti node with free space
+   (e.g. `fsn-node-03.torproject.org`) where the `INSTANCE` will be
+   migrated
+ * `MASTER_NODE`: the master ganeti node
+   (e.g. `fsn-node-01.torproject.org`)
+ * `KVM_HOST`: the machine which we migrate the `INSTANCE` from
+ * the `INSTANCE` has only `root` and `swap` partitions
+
+Import procedure:
+
+ 1. pick a viable SPARE NODE to import the INSTANCE (see "evaluating
+    cluster capacity" above, when in doubt) and find on which KVM HOST
+    the INSTANCE lives
+
+ 2. copy the disks, without downtime:
+ 
+        ./ganeti -v -H $INSTANCE libvirt-import  --ganeti-node $SPARE_NODE --libvirt-host $KVM_HOST
+
+ 3. copy the disks again, this time suspending the machine:
+
+        ./ganeti -v -H $INSTANCE libvirt-import  --ganeti-node $SPARE_NODE --libvirt-host $KVM_HOST --suspend --adopt
+
+ 4. login the new machine through the ganeti console:
+ 
+         gnt-instance console $INSTANCE
+
+ 5. renumber the host:
+    
+        vi /etc/network/interfaces
+        service networking stop
+        service networking start
+
+ 6. test services by changing your `/etc/hosts`
+
+ 7. shutdown original instance:
+ 
+        ssh $INSTANCE shutdown -h +1 'migrating to new server'
+ 
+ 8. destroy test instance:
+ 
+        gnt-instance remove $INSTANCE
+ 
+ 9. redo migration as in step 3, 4 and 5
+
+ 10. final test procedure
+
+ 11. switch to DRBD, still on the Ganeti MASTER NODE:
+
+        gnt-instance stop $INSTANCE
+        gnt-instance modify -t drbd $INSTANCE
+        gnt-instance failover $INSTANCE
+        gnt-instance start $INSTANCE
+
+ 12. switch DNS over to the new machine (see step 16 below)
+
+ 13. retire old instance ([[retire-a-host]])
+
+## Importing external instances, manual
 
 Assumptions: