Reduces terminationGracePeriodSeconds from 180s to 100s (#894)

The 180s termination grace period was to account for the very long time it
could take for mlab-ns to notice that pod was shutting down. With Locate and
Heartbeat, this process only takes 10s. Nothing changes about the configuration
here, except removing unnecessary wait time. Tests still have 30s to complete,
and pusher still has 60s to push data to GCS as fast as it can.

Resolves m-lab/ops-tracker#1742

k8s/daemonsets/templates.jsonnet

@@ -13,12 +13,11 @@ local PROJECT_ID = std.extVar('PROJECT_ID');
 //
 //  * k8s sends SIGTERM to container
 //  * container enables lame duck status
-//  * monitoring reads lame duck status (60s max)
-//  * mlab-ns updates server status (60s max)
+//  * heartbeat notices lame duck status and notifies Locate (10s max)
 //  * all currently running tests complete. (30s max)
-//  * give everything an additional 30s to be safe
-//  * 60s + 60s + 30s + 30s = 180s grace period
-local terminationGracePeriodSeconds = 180;
+//  * give Pusher an additional 60s to upload all data
+//  * 10s + 30s + 60s = 100s grace period
+local terminationGracePeriodSeconds = 100;
 
 local uuid = {
   initContainer: {
@@ -845,7 +844,7 @@ local Experiment(name, index, bucket, anonMode, datatypes=[], datatypesAutoloade
         dnsConfig: {
           nameservers: ['8.8.8.8', '8.8.4.4'],
         },
-        // Only enable extended grace period where production traffic is possible.
+        // Apply extended grace period, except for mlab-sandbox
         [if std.extVar('PROJECT_ID') != 'mlab-sandbox' then 'terminationGracePeriodSeconds']: terminationGracePeriodSeconds,
       },
     },