# Soak Test serve_hostnames
This directory contains the source for a soak test `serve_hostnames` which performs the following actions when used with the GCE provider:
* A connection is established to the master of the cluster identified from the current context set in `$HOME/.kube/.kubeconfig`.
* The nodes available on the cluster are enumerated (say *N* nodes).
* On each node, *M* pods are created (by default 1). The pod encapsulates the `serve_hostnames` image which simply returns the name of the pod in response to a `GET` request.
The pods are created individually (i.e. not with a replication controller).
* A service is created which maps to these pods.
* The program makes *I* iterations (default 1) where it issues *QxNxM* queries (*Q* default is 10) via the service proxy interface at the master.
* The program verifies that every pod (and thus every node) responded to at least one query (the average should be about *Q*).
* The time taken to perform various operations is reported and some operations are re-tried if they failed.
Run the following command:
```sh
./serve_hostnames
```
Here is some representative output:
```
I0326 14:21:04.179893 11434 serve_hostnames.go:60] Starting serve_hostnames soak test with queries=10 and podsPerNode=1 upTo=1
I0326 14:21:04.507252 11434 serve_hostnames.go:85] Nodes found on this cluster:
I0326 14:21:04.507282 11434 serve_hostnames.go:87] 0: kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:21:04.507297 11434 serve_hostnames.go:87] 1: kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:21:04.507309 11434 serve_hostnames.go:87] 2: kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:21:04.507320 11434 serve_hostnames.go:87] 3: kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:21:04.507347 11434 serve_hostnames.go:95] Using namespace serve-hostnames-8145 for this test.
I0326 14:21:04.507363 11434 serve_hostnames.go:98] Creating service serve-hostnames-8145/serve-hostnames
I0326 14:21:04.559849 11434 serve_hostnames.go:148] Creating pod serve-hostnames-8145/serve-hostname-0-0 on node kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:21:04.605603 11434 serve_hostnames.go:148] Creating pod serve-hostnames-8145/serve-hostname-1-0 on node kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:21:04.662099 11434 serve_hostnames.go:148] Creating pod serve-hostnames-8145/serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:21:04.707179 11434 serve_hostnames.go:148] Creating pod serve-hostnames-8145/serve-hostname-3-0 on node kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:21:04.757646 11434 serve_hostnames.go:194] Waiting for the serve-hostname pods to be ready
I0326 14:23:31.125188 11434 serve_hostnames.go:211] serve-hostnames-8145/serve-hostname-0-0 is running
I0326 14:23:31.165984 11434 serve_hostnames.go:211] serve-hostnames-8145/serve-hostname-1-0 is running
I0326 14:25:22.213751 11434 serve_hostnames.go:211] serve-hostnames-8145/serve-hostname-2-0 is running
I0326 14:25:37.387257 11434 serve_hostnames.go:211] serve-hostnames-8145/serve-hostname-3-0 is running
W0326 14:25:39.243813 11434 serve_hostnames.go:265] No response from pod serve-hostname-3-0 on node kubernetes-node-jay1.c.kubernetes-satnam.internal at iteration 0
I0326 14:25:39.243844 11434 serve_hostnames.go:269] Iteration 0 took 1.814483599s for 40 queries (22.04 QPS)
I0326 14:25:39.243871 11434 serve_hostnames.go:182] Cleaning up pods
I0326 14:25:39.434619 11434 serve_hostnames.go:130] Cleaning up service serve-hostnames-8145/server-hostnames
```
The pods are named with -*N*-*M* suffixes which identify the number of the node *N* and the number of the pod *M* on that node.
Notice that in this run the pod (number 0) running on node 3 did not respond to any queries.
The number of iterations to perform for issuing queries can be changed from the default of 1 to some higher value e.g. `--up_to=3` and the number of pods per node can also be changed e.g. `--pods_per_node=2`:
```sh
./serve_hostnames --up_to=3 --pods_per_node=2
```
The output is similar to this:
```
I0326 14:27:27.584378 11808 serve_hostnames.go:60] Starting serve_hostnames soak test with queries=10 and podsPerNode=2 upTo=3
I0326 14:27:27.913713 11808 serve_hostnames.go:85] Nodes found on this cluster:
I0326 14:27:27.913774 11808 serve_hostnames.go:87] 0: kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:27:27.913800 11808 serve_hostnames.go:87] 1: kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:27:27.913825 11808 serve_hostnames.go:87] 2: kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:27:27.913846 11808 serve_hostnames.go:87] 3: kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:27:27.913904 11808 serve_hostnames.go:95] Using namespace serve-hostnames-4997 for this test.
I0326 14:27:27.913931 11808 serve_hostnames.go:98] Creating service serve-hostnames-4997/serve-hostnames
I0326 14:27:27.969083 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-0-0 on node kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:27:28.020133 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-0-1 on node kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:27:28.070054 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-1-0 on node kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:27:28.118641 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-1-1 on node kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:27:28.168786 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:27:28.214730 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-2-1 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:27:28.261685 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-3-0 on node kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:27:28.320224 11808 serve_hostnames.go:148] Creating pod serve-hostnames-4997/serve-hostname-3-1 on node kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:27:28.387007 11808 serve_hostnames.go:194] Waiting for the serve-hostname pods to be ready
I0326 14:28:28.969149 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-0-0 is running
I0326 14:28:29.010376 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-0-1 is running
I0326 14:28:29.050463 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-1-0 is running
I0326 14:28:29.091164 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-1-1 is running
I0326 14:30:00.850461 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-2-0 is running
I0326 14:30:00.891559 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-2-1 is running
I0326 14:30:00.932829 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-3-0 is running
I0326 14:30:00.973941 11808 serve_hostnames.go:211] serve-hostnames-4997/serve-hostname-3-1 is running
W0326 14:30:04.726582 11808 serve_hostnames.go:265] No response from pod serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal at iteration 0
W0326 14:30:04.726658 11808 serve_hostnames.go:265] No response from pod serve-hostname-2-1 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal at iteration 0
I0326 14:30:04.726696 11808 serve_hostnames.go:269] Iteration 0 took 3.711080213s for 80 queries (21.56 QPS)
W0326 14:30:08.267297 11808 serve_hostnames.go:265] No response from pod serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal at iteration 1
W0326 14:30:08.267365 11808 serve_hostnames.go:265] No response from pod serve-hostname-2-1 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal at iteration 1
I0326 14:30:08.267404 11808 serve_hostnames.go:269] Iteration 1 took 3.540635303s for 80 queries (22.59 QPS)
I0326 14:30:11.971349 11808 serve_hostnames.go:269] Iteration 2 took 3.703884372s for 80 queries (21.60 QPS)
I0326 14:30:11.971425 11808 serve_hostnames.go:182] Cleaning up pods
I0326 14:30:12.382932 11808 serve_hostnames.go:130] Cleaning up service serve-hostnames-4997/server-hostnames
```
Notice here that for the first two iterations neither of the pods on node 2 responded but by the third iteration responses
were received from all nodes.
For a soak test use `--up_to=-1` which will loop indefinitely.
Note that this is not designed to be a performance test. The goal for this program is to provide an easy way to have a soak test
that can run indefinitely an exercise enough of Kubernetes' functionality to be confident that the cluster is still up and healthy.
The reported QPS mainly indicates latency to the master since the proxy requests are issued (deliberately) in a serial manner.
A more detailed report can be produced with `--v=4` which measures the time taken to perform various operations
and it also reports the distribution of responses received from the pods. In the example below
we see that the pod on node 0 returned 18 responses, the pod on node 1 returned 10 responses and the
pod on node 3 returned 12 responses and the pod on node 2 did not respond at all.
```sh
./serve_hostnames --v=4
```
The output is similar to this:
```
I0326 14:33:26.020917 12099 serve_hostnames.go:60] Starting serve_hostnames soak test with queries=10 and podsPerNode=1 upTo=1
I0326 14:33:26.365201 12099 serve_hostnames.go:85] Nodes found on this cluster:
I0326 14:33:26.365260 12099 serve_hostnames.go:87] 0: kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:33:26.365288 12099 serve_hostnames.go:87] 1: kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:33:26.365313 12099 serve_hostnames.go:87] 2: kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:33:26.365334 12099 serve_hostnames.go:87] 3: kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:33:26.365392 12099 serve_hostnames.go:95] Using namespace serve-hostnames-1631 for this test.
I0326 14:33:26.365419 12099 serve_hostnames.go:98] Creating service serve-hostnames-1631/serve-hostnames
I0326 14:33:26.423927 12099 serve_hostnames.go:118] Service create serve-hostnames-1631/server-hostnames took 58.473361ms
I0326 14:33:26.423981 12099 serve_hostnames.go:148] Creating pod serve-hostnames-1631/serve-hostname-0-0 on node kubernetes-node-5h4m.c.kubernetes-satnam.internal
I0326 14:33:26.480185 12099 serve_hostnames.go:168] Pod create serve-hostnames-1631/serve-hostname-0-0 request took 56.178906ms
I0326 14:33:26.480271 12099 serve_hostnames.go:148] Creating pod serve-hostnames-1631/serve-hostname-1-0 on node kubernetes-node-9i4n.c.kubernetes-satnam.internal
I0326 14:33:26.534300 12099 serve_hostnames.go:168] Pod create serve-hostnames-1631/serve-hostname-1-0 request took 53.981761ms
I0326 14:33:26.534396 12099 serve_hostnames.go:148] Creating pod serve-hostnames-1631/serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal
I0326 14:33:26.590188 12099 serve_hostnames.go:168] Pod create serve-hostnames-1631/serve-hostname-2-0 request took 55.752115ms
I0326 14:33:26.590222 12099 serve_hostnames.go:148] Creating pod serve-hostnames-1631/serve-hostname-3-0 on node kubernetes-node-jay1.c.kubernetes-satnam.internal
I0326 14:33:26.650024 12099 serve_hostnames.go:168] Pod create serve-hostnames-1631/serve-hostname-3-0 request took 59.781614ms
I0326 14:33:26.650083 12099 serve_hostnames.go:194] Waiting for the serve-hostname pods to be ready
I0326 14:33:32.776651 12099 serve_hostnames.go:211] serve-hostnames-1631/serve-hostname-0-0 is running
I0326 14:33:32.822324 12099 serve_hostnames.go:211] serve-hostnames-1631/serve-hostname-1-0 is running
I0326 14:35:03.741235 12099 serve_hostnames.go:211] serve-hostnames-1631/serve-hostname-2-0 is running
I0326 14:35:03.786411 12099 serve_hostnames.go:211] serve-hostnames-1631/serve-hostname-3-0 is running
I0326 14:35:03.878030 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 45.656425ms
I0326 14:35:03.923999 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 45.887564ms
I0326 14:35:03.967731 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.7004ms
I0326 14:35:04.011077 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.318018ms
I0326 14:35:04.054958 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.843043ms
I0326 14:35:04.099051 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.030505ms
I0326 14:35:04.143197 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.069434ms
I0326 14:35:04.186800 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.530301ms
I0326 14:35:04.230492 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.658239ms
I0326 14:35:04.274337 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.800072ms
I0326 14:35:04.317801 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.379729ms
I0326 14:35:04.362778 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.897882ms
I0326 14:35:04.406845 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.976645ms
I0326 14:35:04.450513 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.613496ms
I0326 14:35:04.494369 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.777934ms
I0326 14:35:04.538399 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.945502ms
I0326 14:35:04.583760 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 45.285171ms
I0326 14:35:04.637430 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 53.629532ms
I0326 14:35:04.681389 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.918124ms
I0326 14:35:04.725401 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.964965ms
I0326 14:35:04.769218 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.734827ms
I0326 14:35:04.812660 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.376494ms
I0326 14:35:04.857974 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 45.246004ms
I0326 14:35:04.901706 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.668478ms
I0326 14:35:04.945372 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.642202ms
I0326 14:35:04.989023 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.619706ms
I0326 14:35:05.033153 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.087168ms
I0326 14:35:05.077038 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.791991ms
I0326 14:35:05.124299 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 47.214038ms
I0326 14:35:05.168162 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.795225ms
I0326 14:35:05.211687 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.48304ms
I0326 14:35:05.255553 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.799647ms
I0326 14:35:05.299352 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.72493ms
I0326 14:35:05.342916 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.509589ms
I0326 14:35:05.386952 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.947881ms
I0326 14:35:05.431467 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.442041ms
I0326 14:35:05.475834 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.304759ms
I0326 14:35:05.519373 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.501574ms
I0326 14:35:05.563584 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 44.162687ms
I0326 14:35:05.607126 12099 serve_hostnames.go:249] Proxy call in namespace serve-hostnames-1631 took 43.478674ms
I0326 14:35:05.607164 12099 serve_hostnames.go:258] serve-hostname-3-0: 12
I0326 14:35:05.607176 12099 serve_hostnames.go:258] serve-hostname-1-0: 10
I0326 14:35:05.607186 12099 serve_hostnames.go:258] serve-hostname-0-0: 18
W0326 14:35:05.607199 12099 serve_hostnames.go:265] No response from pod serve-hostname-2-0 on node kubernetes-node-d0yo.c.kubernetes-satnam.internal at iteration 0
I0326 14:35:05.607211 12099 serve_hostnames.go:269] Iteration 0 took 1.774856469s for 40 queries (22.54 QPS)
I0326 14:35:05.607236 12099 serve_hostnames.go:182] Cleaning up pods
I0326 14:35:05.797893 12099 serve_hostnames.go:130] Cleaning up service serve-hostnames-1631/server-hostnames
```
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