From 9f4ec648b486fc05d5846ff5f36993d58d337ad1 Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Mon, 7 Sep 2015 00:06:41 -0400
Subject: [PATCH] AWS: Create one storage pool for aufs, not two

We were splitting the aufs storage into docker & kubernetes areas, but
the kubernetes area was filling up very quickly because empty volumes
went on there, and I had originally not sized it big enough for that.

Instead, create one volume for both so they can share space freely.  We
can't do this for devicemapper, but that configuration seems to be
deprecated by Docker anyway.
---
 cluster/aws/templates/format-disks.sh | 56 +++++++++++++++------------
 1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/cluster/aws/templates/format-disks.sh b/cluster/aws/templates/format-disks.sh
index adebf1568b8..102e092f674 100644
--- a/cluster/aws/templates/format-disks.sh
+++ b/cluster/aws/templates/format-disks.sh
@@ -118,45 +118,51 @@ else
       # This is the best option, but it is sadly broken on most distros
       # Bug: https://github.com/docker/docker/issues/4036
 
-      # 95% goes to the docker thin-pool
-      lvcreate -l 95%VG --thinpool docker-thinpool vg-ephemeral
+      # 80% goes to the docker thin-pool; we want to leave some space for host-volumes
+      lvcreate -l 80%VG --thinpool docker-thinpool vg-ephemeral
 
       DOCKER_OPTS="${DOCKER_OPTS} --storage-opt dm.thinpooldev=/dev/mapper/vg--ephemeral-docker--thinpool"
       # Note that we don't move docker; docker goes direct to the thinpool
-    else
+
+      # Remaining space (20%) is for kubernetes data
+      # TODO: Should this be a thin pool?  e.g. would we ever want to snapshot this data?
+      lvcreate -l 100%FREE -n kubernetes vg-ephemeral
+      mkfs -t ext4 /dev/vg-ephemeral/kubernetes
+      mkdir -p /mnt/ephemeral/kubernetes
+      echo "/dev/vg-ephemeral/kubernetes  /mnt/ephemeral/kubernetes  ext4  noatime  0 0" >> /etc/fstab
+      mount /mnt/ephemeral/kubernetes
+
+      move_kubelet="/mnt/ephemeral/kubernetes"
+     else
       # aufs
 
-      # Create a docker lv, use docker on it
-      # 95% goes to the docker thin-pool
+      # We used to split docker & kubernetes, but we no longer do that, because
+      # host volumes go into the kubernetes area, and it is otherwise very easy
+      # to fill up small volumes.
+
       release=`lsb_release -c -s`
       if [[ "${release}" != "wheezy" ]] ; then
-        lvcreate -l 95%VG --thinpool docker-thinpool vg-ephemeral
+        lvcreate -l 100%FREE --thinpool pool-ephemeral vg-ephemeral
 
-        THINPOOL_SIZE=$(lvs vg-ephemeral/docker-thinpool -o LV_SIZE --noheadings --units M --nosuffix)
-        lvcreate -V${THINPOOL_SIZE}M -T vg-ephemeral/docker-thinpool -n docker
+        THINPOOL_SIZE=$(lvs vg-ephemeral/pool-ephemeral -o LV_SIZE --noheadings --units M --nosuffix)
+        lvcreate -V${THINPOOL_SIZE}M -T vg-ephemeral/pool-ephemeral -n ephemeral
       else
         # Thin provisioning not supported by Wheezy
         echo "Detected wheezy; won't use LVM thin provisioning"
-        lvcreate -l 95%VG -n docker vg-ephemeral
+        lvcreate -l 100%VG -n ephemeral vg-ephemeral
       fi
 
-      mkfs -t ext4 /dev/vg-ephemeral/docker
-      mkdir -p /mnt/ephemeral/docker
-      echo "/dev/vg-ephemeral/docker  /mnt/ephemeral/docker  ext4  noatime  0 0" >> /etc/fstab
-      mount /mnt/ephemeral/docker
+      mkfs -t ext4 /dev/vg-ephemeral/ephemeral
+      mkdir -p /mnt/ephemeral
+      echo "/dev/vg-ephemeral/ephemeral  /mnt/ephemeral  ext4  noatime  0 0" >> /etc/fstab
+      mount /mnt/ephemeral
+
+      mkdir -p /mnt/ephemeral/kubernetes
+
       move_docker="/mnt/ephemeral"
-    fi
-
-    # Remaining 5% is for kubernetes data
-    # TODO: Should this be a thin pool?  e.g. would we ever want to snapshot this data?
-    lvcreate -l 100%FREE -n kubernetes vg-ephemeral
-    mkfs -t ext4 /dev/vg-ephemeral/kubernetes
-    mkdir -p /mnt/ephemeral/kubernetes
-    echo "/dev/vg-ephemeral/kubernetes  /mnt/ephemeral/kubernetes  ext4  noatime  0 0" >> /etc/fstab
-    mount /mnt/ephemeral/kubernetes
-
-    move_kubelet="/mnt/ephemeral/kubernetes"
-  else
+      move_kubelet="/mnt/ephemeral/kubernetes"
+     fi
+ else
     echo "Ignoring unknown DOCKER_STORAGE: ${docker_storage}"
   fi
 fi