Add support for preemptible GCP instances

net/scripts/azure-provider.sh

@@ -8,6 +8,10 @@ cloud_DefaultZone() {
   echo "westus"
 }
 
+cloud_RestartPreemptedInstances() {
+  : # Not implemented
+}
+
 #
 # __cloud_GetConfigValueFromInstanceName
 # Return a piece of configuration information about an instance

net/scripts/colo-provider.sh

@@ -16,6 +16,10 @@ cloud_DefaultZone() {
   echo "Denver"
 }
 
+cloud_RestartPreemptedInstances() {
+  : # Not implemented
+}
+
 #
 # __cloud_FindInstances
 #
@@ -134,6 +138,7 @@ cloud_Initialize() {
 #                 has been provisioned in the GCE region that is hosting `$zone`
 # bootDiskType  - Optional specify SSD or HDD boot disk
 # additionalDiskSize - Optional specify size of additional storage volume
+# preemptible - Optionally request a preemptible instance ("true")
 #
 # Tip: use cloud_FindInstances to locate the instances once this function
 #      returns
@@ -149,7 +154,8 @@ cloud_CreateInstances() {
   #declare optionalAddress="$9" # unused
   #declare optionalBootDiskType="${10}" # unused
   #declare optionalAdditionalDiskSize="${11}" # unused
-  declare sshPrivateKey="${12}"
+  #declare optionalPreemptible="${12}" # unused
+  declare sshPrivateKey="${13}"
 
   declare -a nodes
   if [[ $numNodes = 1 ]]; then

net/scripts/ec2-provider.sh

@@ -7,6 +7,10 @@ cloud_DefaultZone() {
   echo "us-east-1b"
 }
 
+cloud_RestartPreemptedInstances() {
+  : # Not implemented
+}
+
 # AWS region is zone with the last character removed
 __cloud_GetRegion() {
   declare zone="$1"

net/scripts/gce-provider.sh

@@ -8,6 +8,29 @@ cloud_DefaultZone() {
   echo "us-west1-b"
 }
 
+#
+# cloud_RestartPreemptedInstances [namePrefix]
+#
+# Restart any preempted instances matching the specified prefix
+#
+# namePrefix - The instance name prefix of the preempted instances
+#
+cloud_RestartPreemptedInstances() {
+  declare filter="$1"
+
+  declare name status zone
+  while read -r name status zone; do
+    echo "Starting $status instance: $name"
+    (
+      set -x
+      gcloud compute instances start --zone "$zone" "$name"
+    )
+  done < <(gcloud compute instances list \
+             --filter "$filter" \
+             --format 'value(name,status,zone)' \
+           | grep TERMINATED)
+}
+
 #
 # __cloud_FindInstances
 #
@@ -125,6 +148,7 @@ cloud_Initialize() {
 #                 has been provisioned in the GCE region that is hosting `$zone`
 # bootDiskType  - Optional specify SSD or HDD boot disk
 # additionalDiskSize - Optional specify size of additional storage volume
+# preemptible - Optionally request a preemptible instance ("true")
 #
 # Tip: use cloud_FindInstances to locate the instances once this function
 #      returns
@@ -140,6 +164,8 @@ cloud_CreateInstances() {
   declare optionalAddress="$9"
   declare optionalBootDiskType="${10}"
   declare optionalAdditionalDiskSize="${11}"
+  declare optionalPreemptible="${12}"
+  #declare sshPrivateKey="${13}"  # unused
 
   if $enableGpu; then
     # Custom Ubuntu 18.04 LTS image with CUDA 9.2 and CUDA 10.0 installed
@@ -176,6 +202,10 @@ cloud_CreateInstances() {
   # shellcheck disable=SC2206 # Do not want to quote $imageName as it may contain extra args
   args+=(--image $imageName)
 
+  if [[ $optionalPreemptible = true ]]; then
+    args+=(--preemptible)
+  fi
+
   # shellcheck disable=SC2206 # Do not want to quote $machineType as it may contain extra args
   for word in $machineType; do
     # Special handling for the "--min-cpu-platform" argument which may contain a