hack/*: GC kubelet rkt images after run.

This PR changes the cloud-config data in the hack dir so that it
stores the rkt UUID for the kubelet pod, and gc the stopped ones.

Fix #218

Author: Yifan Gu

hack/multi-node/user-data.sample

@@ -10,12 +10,15 @@ coreos:
         EnvironmentFile=/etc/environment
         Environment=KUBELET_ACI=quay.io/coreos/hyperkube
         Environment=KUBELET_VERSION=v1.5.3_coreos.0
-        Environment="RKT_OPTS=--volume var-lib-cni,kind=host,source=/var/lib/cni --mount volume=var-lib-cni,target=/var/lib/cni"
+        Environment="RKT_OPTS=--uuid-file-save=/var/run/kubelet-pod.uuid \
+          --volume var-lib-cni,kind=host,source=/var/lib/cni \
+          --mount volume=var-lib-cni,target=/var/lib/cni"
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/manifests
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/cni/net.d
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/checkpoint-secrets
         ExecStartPre=/bin/mkdir -p /srv/kubernetes/manifests
         ExecStartPre=/bin/mkdir -p /var/lib/cni
+        ExecStartPre=-/usr/bin/rkt rm --uuid-file=/var/run/kubelet-pod.uuid
         ExecStart=/usr/lib/coreos/kubelet-wrapper \
           --kubeconfig=/etc/kubernetes/kubeconfig \
           --experimental-bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubeconfig \
@@ -31,6 +34,8 @@ coreos:
           --node-labels=master=true \
           --cluster_dns=10.3.0.10 \
           --cluster_domain=cluster.local
+
+        ExecStop=-/usr/bin/rkt stop --uuid-file=/var/run/kubelet-pod.uuid
         Restart=always
         RestartSec=5
 

hack/quickstart/kubelet.master

@@ -2,6 +2,7 @@
 Environment=KUBELET_ACI=quay.io/coreos/hyperkube
 Environment=KUBELET_VERSION=v1.5.3_coreos.0
 Environment="RKT_OPTS=\
+--uuid-file-save=/var/run/kubelet-pod.uuid \
 --volume etc-resolv,kind=host,source=/etc/resolv.conf --mount volume=etc-resolv,target=/etc/resolv.conf \
 --volume var-lib-cni,kind=host,source=/var/lib/cni --mount volume=var-lib-cni,target=/var/lib/cni"
 EnvironmentFile=/etc/environment
@@ -10,6 +11,7 @@ ExecStartPre=/bin/mkdir -p /etc/kubernetes/cni/net.d
 ExecStartPre=/bin/mkdir -p /etc/kubernetes/checkpoint-secrets
 ExecStartPre=/bin/mkdir -p /srv/kubernetes/manifests
 ExecStartPre=/bin/mkdir -p /var/lib/cni
+ExecStartPre=-/usr/bin/rkt rm --uuid-file=/var/run/kubelet-pod.uuid
 ExecStart=/usr/lib/coreos/kubelet-wrapper \
   --kubeconfig=/etc/kubernetes/kubeconfig \
   --experimental-bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubeconfig \
@@ -27,6 +29,7 @@ ExecStart=/usr/lib/coreos/kubelet-wrapper \
   --cluster_domain=cluster.local \
   --config=/etc/kubernetes/manifests
 
+ExecStop=-/usr/bin/rkt stop --uuid-file=/var/run/kubelet-pod.uuid
 Restart=always
 RestartSec=5
 

hack/quickstart/kubelet.worker

@@ -2,12 +2,14 @@
 Environment=KUBELET_ACI=quay.io/coreos/hyperkube
 Environment=KUBELET_VERSION=v1.5.3_coreos.0
 Environment="RKT_OPTS=\
+--uuid-file-save=/var/run/kubelet-pod.uuid \
 --volume etc-resolv,kind=host,source=/etc/resolv.conf --mount volume=etc-resolv,target=/etc/resolv.conf \
 --volume var-lib-cni,kind=host,source=/var/lib/cni --mount volume=var-lib-cni,target=/var/lib/cni"
 EnvironmentFile=/etc/environment
 ExecStartPre=/bin/mkdir -p /etc/kubernetes/manifests
 ExecStartPre=/bin/mkdir -p /etc/kubernetes/cni/net.d
 ExecStartPre=/bin/mkdir -p /var/lib/cni
+ExecStartPre=-/usr/bin/rkt rm --uuid-file=/var/run/kubelet-pod.uuid
 ExecStart=/usr/lib/coreos/kubelet-wrapper \
   --kubeconfig=/etc/kubernetes/kubeconfig \
   --experimental-bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubeconfig \
@@ -24,6 +26,7 @@ ExecStart=/usr/lib/coreos/kubelet-wrapper \
   --cluster_domain=cluster.local \
   --config=/etc/kubernetes/manifests
 
+ExecStop=-/usr/bin/rkt stop --uuid-file=/var/run/kubelet-pod.uuid
 Restart=always
 RestartSec=5
 

hack/single-node/user-data.sample

@@ -18,12 +18,15 @@ coreos:
         EnvironmentFile=/etc/environment
         Environment=KUBELET_ACI=quay.io/coreos/hyperkube
         Environment=KUBELET_VERSION=v1.5.3_coreos.0
-        Environment="RKT_OPTS=--volume var-lib-cni,kind=host,source=/var/lib/cni --mount volume=var-lib-cni,target=/var/lib/cni"
+        Environment="RKT_OPTS=--uuid-file-save=/var/run/kubelet-pod.uuid \
+          --volume var-lib-cni,kind=host,source=/var/lib/cni \
+          --mount volume=var-lib-cni,target=/var/lib/cni"
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/manifests
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/cni/net.d
         ExecStartPre=/bin/mkdir -p /etc/kubernetes/checkpoint-secrets
         ExecStartPre=/bin/mkdir -p /srv/kubernetes/manifests
         ExecStartPre=/bin/mkdir -p /var/lib/cni
+        ExecStartPre=-/usr/bin/rkt rm --uuid-file=/var/run/kubelet-pod.uuid
         ExecStart=/usr/lib/coreos/kubelet-wrapper \
           --kubeconfig=/etc/kubernetes/kubeconfig \
           --experimental-bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubeconfig \
@@ -40,6 +43,7 @@ coreos:
           --cluster_dns=10.3.0.10 \
           --cluster_domain=cluster.local
 
+        ExecStop=-/usr/bin/rkt stop --uuid-file=/var/run/kubelet-pod.uuid
         Restart=always
         RestartSec=5