Suspend AZRebalance

load-balancing/elb/README.md

@@ -29,6 +29,8 @@ in the CLI's user guide.
     autoscaling:EnterStandby
     autoscaling:ExitStandby
     autoscaling:UpdateAutoScalingGroup
+    autoscaling:SuspendProcesses
+    autoscaling:ResumeProcesses
 ```
 
 Note: the AWS CodeDeploy Agent requires that an instance profile be attached to all instances that

load-balancing/elb/common_functions.sh

@@ -101,6 +101,26 @@ autoscaling_enter_standby() {
         return 0
     fi
 
+    msg "Checking to see if ASG ${asg_name} had AZRebalance process suspended previously"
+    local azrebalance_suspended=$($AWS_CLI autoscaling describe-auto-scaling-groups \
+        --auto-scaling-group-name "${asg_name}" \
+        --query 'AutoScalingGroups[].SuspendedProcesses' \
+        --output text | grep -c 'AZRebalance')
+    if [ $azrebalance_suspended -eq 1 ]; then
+        msg "ASG ${asg_name} had AZRebalance suspended, creating flag file /tmp/azrebalanced"
+        # Create a "flag" file to denote that the ASG had AZRebalance enabled
+        touch /tmp/azrebalanced
+    else
+        msg "ASG ${asg_name} didn't have AZRebalance suspended, suspending"
+        $AWS_CLI autoscaling suspend-processes \
+            --auto-scaling-group-name "${asg_name}" \
+            --scaling-processes AZRebalance
+        if [ $? != 0 ]; then
+            msg "Failed to suspend the AZRebalance process for ASG ${asg_name}. Aborting as this may cause issues."
+            return 1
+        fi
+    fi
+
     msg "Checking to see if ASG ${asg_name} will let us decrease desired capacity"
     local min_desired=$($AWS_CLI autoscaling describe-auto-scaling-groups \
         --auto-scaling-group-name "${asg_name}" \
@@ -217,6 +237,21 @@ autoscaling_exit_standby() {
         msg "Auto scaling group was not decremented previously, not incrementing min value"
     fi
 
+    if [ -a /tmp/azrebalanced ]; then
+        msg "ASG ${asg_name} had AZRebalance suspended previously, leaving it suspended"
+        msg "Removing /tmp/azrebalanced flag file"
+        rm -f /tmp/azrebalanced
+    else
+        msg "Resuming AZRebalance process for ASG ${asg_name}"
+        $AWS_CLI autoscaling resume-processes \
+            --auto-scaling-group-name "${asg_name}" \
+            --scaling-processes AZRebalance
+        if [ $? != 0 ]; then
+            msg "Failed to resume the AZRebalance process for ASG ${asg_name}. This may cause issues!"
+            return 1
+        fi
+    fi
+
     return 0
 }