Initial implementation of Guestbook example #11

lukehoban · 2018-02-13T18:39:56Z

Add a copy of the Guestbook example based on https://kubernetes.io/docs/tutorials/stateless-application/guestbook/.

Also move to use a fork of the Terraform Kubernetes provider which supports Deployment (and other newer) Kubernetes resources. We may need to maintain our own fork to provide a more stable baseline.

Fixes #4.

Add a copy of the Guestbook example based on https://kubernetes.io/docs/tutorials/stateless-application/guestbook/. Also move to use a fork of the Terraform Kubernetes provider which supports Deployment (and other newer) Kubernetes resources. We may need to maintain our own fork to provide a more stable baseline.

LoadBalancer isn't necessarily always supported - including apparently on our Travis Minikube setup.

joeduffy

Great to see this coming alive!

joeduffy · 2018-02-13T20:29:28Z

Gopkg.toml

@@ -35,7 +35,8 @@

 [[constraint]]
  name = "github.com/terraform-providers/terraform-provider-kubernetes"
-  version = "1.0.1"
+  source = "github.com/sl1pm4t/terraform-provider-kubernetes"


I'm slightly nervous about depending on an unofficial fork. If we do this, let's make sure to file a bug to track. Do you know of the plans to merge this in, and/or the overall roadmap for Kubernetes support? Is this something we're going to have to take into our own hands?

Agreed. Kubernetes is not in practice particularly usable in the state it's in in the mainline TF provider. Seems that almost everyone using it in practice is using some fork. There are lots though, and no one that is clearly on track to get merged to mainline.

We will need to work with either TF folks or with one of the fork maintainers to have a robust plan here.

But I don't think there is any world where we can have a valuable Kubernetes story without supporting these resources - so it's just a questions of if/when we depend on them via the mainline or via some fork that community + ourselves commit to making sure is in good state.

hashicorp/terraform-provider-kubernetes#3
hashicorp/terraform-provider-kubernetes#70
hashicorp/terraform-provider-kubernetes#100
hashicorp/terraform-provider-kubernetes#101

I suggest we create our own fork, depend on that, and set it for now to match the one I'm using here. We can then reach our to the maintainer of that, ask that he open a PR against mainline, and help advocate for that PR getting merged.

Ok, surprising that the community is in this state, but maybe it's good news in that it's an area we can help with and help the community.

As to our own fork, I'm happy with that approach, that's consistent with our other providers.

joeduffy · 2018-02-13T20:30:58Z

examples/guestbook/index.ts

+import * as pulumi from "pulumi";
+import * as kubernetes from "@pulumi/kubernetes";
+
+// REDIS MASTER


Instead of a single file, is it worth breaking this apart more similar to https://github.com/kubernetes/kubernetes/tree/master/examples/guestbook? Feels like this will make it a little easier to consume in addition to being more familiar to those who have seen that example code.

FWIW, there's a Ksonnet example here https://github.com/ksonnet/ksonnet/blob/master/examples/guestbook.jsonnet which is a single file. May be worth looking at that for inspiration for what "abstractions", if any, might make sense to introduce in the name of shrinking the example even further.

I think it's only separate files in the default guestbook example so that the tutorial can deploy one part at a time and talk about it that way. Like in the ksonnet version, I'd rather find ways to introduce abstractions to simplify the existing code so that it's easier to read in one file. It's rather insane the mount of text needed to do what is logically a very simple set of work here.

Agree. I wrote this before looking at the Ksonnet example and I definitely like the idea of using abstractions to simplify to the point where it obviously belongs in one file 😄

joeduffy · 2018-02-13T20:31:30Z

examples/guestbook/index.ts

+
+// REDIS MASTER
+
+let redisMasterLabels = { app: "redis", tier: "backend", role: "master"};


Nice, variable reuse 😀

joeduffy · 2018-02-13T20:33:08Z

examples/guestbook/index.ts

+    spec: [{
+        selector: [redisMasterLabels],
+        replicas: 1,
+        strategy: [],


Can this be omitted? (It isn't in the original YAML/Ksonnet examples.)

Yes - it can - dropped.

joeduffy · 2018-02-13T20:33:49Z

examples/guestbook/index.ts

+        name: "redis-master",
+    }],
+    spec: [{
+        selector: [redisMasterLabels],


I didn't see the selector in the YAML/Ksonnet example. Is this correct?

This one: https://github.com/kubernetes/examples/blob/master/guestbook/redis-master-deployment.yaml#L6?

Ah sorry guess I totally missed that!

joeduffy · 2018-02-13T20:38:51Z

examples/guestbook/index.ts

+    spec: [{
+        selector: [redisSlaveLabels],
+        replicas: 1,
+        strategy: [],


Can we omit?

joeduffy · 2018-02-13T20:38:58Z

examples/guestbook/index.ts

+    spec: [{
+        selector: [frontendLabels],
+        replicas: 3,
+        strategy: [],


Can we omit?

joeduffy · 2018-02-13T20:42:03Z

examples/guestbook/index.ts

+        selector: [redisMasterLabels],
+    }],
+});
+let redisMasterDeployment = new kubernetes.Deployment("redis-master", {


Regarding Ksonnet, it's interesting that they got the creation of services down to a single line, and it's done by the service borrowing fields from the deployment:

redis_master_service: example.service("redis-master") { targetPod_: $.redis_master_deployment.spec.template, },

I assume that's just a simple helper library? Is there any way to get this cheaply "inline" in this file?

joeduffy · 2018-02-13T20:43:04Z

examples/guestbook/index.ts

+        labels: [frontendLabels],
+    }],
+    spec: [{
+        type: "NodePort",


This seems different from the example at https://github.com/kubernetes/kubernetes/blob/master/examples/guestbook/frontend-service.yaml, which says:

spec: # if your cluster supports it, uncomment the following to automatically create # an external load-balanced IP for the frontend service. # type: LoadBalancer ports: - port: 80 selector: app: guestbook tier: frontend

Intentional?

The copy of this in the actual walkthrough uses NodePort by default, but then has notes about optionally using LoadBalancer.

Unfortunately, neither appears to work correctly on Docker for Mac Kubernetes install currently. There's lots of mentions of problems with this on the web - including this issue explicitly asking for documentation of what is actually supported: docker/docs#5690.

I do want this example to ultimately be able to provide an output property with a URL you can open in the browser to try the app. It seems that may not be possible with deployments to Docker for Mac today. And cannot in general be done in a a single consistent way across providers with Kubernetes. 😢

joeduffy · 2018-02-13T20:44:25Z

examples/guestbook/index.ts

+    }],
+});
+
+export let frontendPort: pulumi.Output<number> = frontendService.spec.apply(spec => spec[0].port![0].nodePort);


Curious...why is the ! required here?

Also, is the pulumi.Output<number> part required too? Seems strange to explicitly type it.

Also, use pulumi fork of provider.

lukehoban · 2018-02-20T02:48:59Z

Going ahead and merging this, as a raw translation of the core Guestbook.

We would like to have a version more like that ksonnet version, with useful custom helpers for composing and reusing pieces of the specification - but that is largely dependent on solving #12.

lukehoban requested a review from subhabh February 13, 2018 18:40

lukehoban added 2 commits February 13, 2018 12:06

Add guestbook to integration tests

2f74594

Use NodePort instead of LoadBalancer

539177d

LoadBalancer isn't necessarily always supported - including apparently on our Travis Minikube setup.

joeduffy reviewed Feb 13, 2018

View reviewed changes

Cleanup to align more closely with source version

da5ff28

Also, use pulumi fork of provider.

lukehoban merged commit 7ba71a7 into master Feb 20, 2018

lukehoban deleted the 4_guestbook branch February 20, 2018 02:49

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lukehoban commented Feb 20, 2018


		// REDIS MASTER

		let redisMasterLabels = { app: "redis", tier: "backend", role: "master"};

Initial implementation of Guestbook example #11

Initial implementation of Guestbook example #11

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lukehoban commented Feb 20, 2018