Demo application for "Kubernetes Up and Running"

Running

kubectl run --restart=Never --image=gcr.io/kuar-demo/kuard-amd64:1 kuard
kubectl port-forward kuard 8080:8080

Open your browser to http://localhost:8080.

Building

Automated container build and push

This will build and push container images to a registry. It uses gcloud to push to GCR by default. You can edit rules.mk to change this.

This builds a set of images with "fake versions" to be able to play with upgrades.

make push REGISTRY=<my-gcr-registry>

Manual docker build

For those following along with the book, you can build a binary to include in a docker image with a simple make build. This will drop a kuard binary into bin/1/amd64.

You can then build a docker image with the following Dockerfile:

FROM alpine
COPY bin/1/amd64/kuard /kuard
ENTRYPOINT ["/kuard"]

Then build with docker with something like docker build -t kuard-amd64:1 .

KeyGen Workload

To help simulate batch workers, we have a synthetic workload of generating 4096 bit RSA keys. This can be configured through the UI or the command line.

--keygen-enable               Enable KeyGen workload
--keygen-exit-code int        Exit code when workload complete
--keygen-exit-on-complete     Exit after workload is complete
--keygen-memq-queue string    The MemQ server queue to use. If MemQ is used, other limits are ignored.
--keygen-memq-server string   The MemQ server to draw work items from.  If MemQ is used, other limits are ignored.
--keygen-num-to-gen int       The number of keys to generate. Set to 0 for infinite
--keygen-time-to-run int      The target run time in seconds. Set to 0 for infinite

MemQ server

We also have a simple in memory queue with REST API. This is based heavily on https://github.com/kelseyhightower/memq.

The API is as follows with URLs being relative to <server addr>/memq/server. See pkg/memq/types.go for the data structures returned.

Method	Url	Desc
GET	/stats	Get stats on all queues
PUT	/queues/:queue	Create a queue
DELETE	/queues/:queue	Delete a queue
POST	/queues/:queue/drain	Discard all items in queue
POST	/queues/:queue/enqueue	Add item to queue. Body is plain text. Response is message object.
POST	/queues/:queue/dequeue	Grab an item off the queue and return it. Returns a 204 "No Content" if queue is empty.

Versions

Images built will automatically have the git verison (based on tag) applied. In addition, there is an idea of a "fake version". This is used so that we can use the same basic server to demonstrate upgrade scenarios.

Right now we create 3 fake versions: 1, 2, and 3. This translates into the following container images:

gcr.io/kuar-demo/kuard-amd64:v0.4-1
gcr.io/kuar-demo/kuard-amd64:1
gcr.io/kuar-demo/kuard-amd64:v0.4-2
gcr.io/kuar-demo/kuard-amd64:2
gcr.io/kuar-demo/kuard-amd64:v0.4-3
gcr.io/kuar-demo/kuard-amd64:3

For documentation where you want to demonstrate using versions but use the latest version of this server, you can simply reference gcr.io/kuar-demo/kuard-amd64:1. You can then demonstrate an upgrade with gcr.io/kuar-demo/kuard-amd64:2.

(Another way to think about it is that :1 is essentially :latest-1)

We also build versions for arm, arm64, and ppc64le. Just substitute the appropriate architecture in the image name. These aren't as well tested as the amd64 version but seem to work okay.

Development

If you just want to do Go server development, you can build the client as part of a build make. It'll drop the result in to sitedata/built/.

If you want to do both Go server and React.js client dev, you need to do the following:

1. Have Node installed
2. In one terminal

• cd client
• npm install
• npm start
• This will start a debug node server on localhost:8081. It'll proxy all unhandled requests to localhost:8080

3. In another terminal

• Ensure that $GOPATH is set to the directory with your go source code and binaries + ensure that $GOPATH is part of $PATH.
• go get -u github.com/jteeuwen/go-bindata/...
• go generate ./pkg/...
• go run cmd/kuard/*.go --debug

4. Open your browser to http://localhost:8081.

This should support live reload of any changes to the client. The Go server will need to be exited and restarted to see changes.

Makefiles

Go building makefiles taken from https://github.com/thockin/go-build-template with an Apache 2.0 license. Handling multiple targets taken from https://github.com/bowei/go-build-template.

These have been heavily modified.

• Support explicit docker volume for caching vs. using host mounts (as they are really slow on macOS)
• Building/caching node
• Fake versions so we can play with upgrades of this server

TODO

• Make file system browser better. Show size, permissions, etc. Might be able to do this by faking out an index.html as part of the http.FileSystem stuff.
• Clean up form for keygen workload. It is too big and the form build doesn't have enough flexibility to really shrink it down.