peekaboo

Rackspace load balancing toggler for your host's services.

Goal: Automagically connect and disconnect applications to Rackspace load balancers as they come online or are taken offline.

Example run

Start with a fresh host with Docker (or use a built binary):

$ docker run --net=host \
           -e LOAD_BALANCER_ID=8675309 \
           -e OS_USERNAME=rgbkrk \
           -e OS_REGION_NAME=IAD \
           -e OS_PASSWORD=deadbeef13617 \
           rgbkrk/peekaboo
2014/12/12 06:36:49 $APP_PORT not set, defaulting to 80
2014/12/12 06:36:51 Setting 10.184.12.147:80 to be ENABLED on load balancer 64965
2014/12/12 06:36:51 Creating new node
2014/12/12 06:36:53 Final node state: {10.184.12.147 256073 80 ONLINE ENABLED 1 PRIMARY}

Awesome, this host is now connected to the load balancer. Now drain connections from it!

$ docker run --net=host \
           -e LOAD_BALANCER_ID=8675309 \
           -e OS_USERNAME=rgbkrk \
           -e OS_REGION_NAME=IAD \
           -e OS_PASSWORD=deadbeef13617 \
           rgbkrk/peekaboo -drain
2014/12/12 06:37:01 $APP_PORT not set, defaulting to 80
2014/12/12 06:37:02 Setting 10.184.12.147:80 to be DRAINING on load balancer 64965
2014/12/12 06:37:02 Updating existing node {10.184.12.147 256073 80 ONLINE ENABLED 0 PRIMARY}
2014/12/12 06:37:06 Final node state: {10.184.12.147 256073 80 ONLINE DRAINING 1 PRIMARY}

Back online for good measure:

$ docker run --net=host \
           -e LOAD_BALANCER_ID=8675309 \
           -e OS_USERNAME=rgbkrk \
           -e OS_REGION_NAME=IAD \
           -e OS_PASSWORD=deadbeef13617 \
           rgbkrk/peekaboo
2014/12/12 06:37:18 $APP_PORT not set, defaulting to 80
2014/12/12 06:37:20 Setting 10.184.12.147:80 to be ENABLED on load balancer 64965
2014/12/12 06:37:20 Updating existing node {10.184.12.147 256073 80 ONLINE DRAINING 0 PRIMARY}
2014/12/12 06:37:23 Final node state: {10.184.12.147 256073 80 ONLINE ENABLED 1 PRIMARY}

Now kill it entirely:

$ docker run --net=host \
           -e LOAD_BALANCER_ID=8675309 \
           -e OS_USERNAME=rgbkrk \
           -e OS_REGION_NAME=IAD \
           -e OS_PASSWORD=deadbeaf13617 \
           rgbkrk/peekaboo -delete
2015/06/23 13:03:48 Deleting existing node {10.209.136.41 938559 80 ONLINE DRAINING 0 PRIMARY}
2015/06/23 13:03:48 Final node state: Deleted

Configuration

Load Balancer ID

Set environment variable LOAD_BALANCER_ID to the ID of the Load Balancer you wish to connect servers to. The load balancer must exist ahead of time.

The ID can be found on the details page for the load balancer in your Rackspace control panel.

Rackspace Credentials and Region

We use the standard OpenStack environment variable names here:

OS_USERNAME - User name to log in to the Rackspace control panel
OS_PASSWORD - API Key for Rackspace
OS_REGION_NAME - Any one of IAD, DFW, HKG, SYD, ORD (haven't tested LON)

IP Address

Peekaboo will try to determine what IP to use with the load balancer. It does this by looking for a 10.x.x.x IPv4 address on the host then by looking for an eth0 interface.

If you need control you can set the -ip flag (e.g. -ip 192.168.1.3 or define one of two environment variables (adopted from coreos-cluster): RAX_SERVICENET_IPV4 or RAX_PUBLICNET_IPV4.

Precedence order:

-ip flag
$RAX_SERVICENET_IPV4
$RAX_PUBLICNET_IPV4
Gleaning a 10 dot out of the network interfaces (most likely)
IPv4 address from eth0 (last ditch option)

Application port

Set $APP_PORT or just let 80 be the default. Your choice.

ROADMAP

Enable node on load balancer
Drain node off load balancer conditionally
Get IP Address from an interface
Create basic fleet service file example
Set up Docker build that builds straight from source
Set up Docker build that packages just the binary build
Determine when the node has terminated connections after DRAINING, set to DISABLED and allow follow on processes to continue (CoreOS update, fleet movement)

Hacking

Clone this into the right spot on your $GOPATH and then

go get
go build

Statically linked Go binary without debugging (dwarf)

Drop the built executable to ~6.1MB from ~8.2MB, courtesy kelseyhightower:

CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w' .

~/go/src/github.com/rgbkrk/peekaboo$ go build
~/go/src/github.com/rgbkrk/peekaboo$ cp peekaboo peekaboo.default
~/go/src/github.com/rgbkrk/peekaboo$ CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w' .
~/go/src/github.com/rgbkrk/peekaboo$ ls -lah
total 15M
drwxrwxr-x 3 rgbkrk rgbkrk 4.0K Dec 12 05:30 .
drwxrwxr-x 3 rgbkrk rgbkrk 4.0K Dec 12 05:25 ..
drwxrwxr-x 8 rgbkrk rgbkrk 4.0K Dec 12 05:30 .git
-rw-rw-r-- 1 rgbkrk rgbkrk  276 Dec 12 05:25 .gitignore
-rw-rw-r-- 1 rgbkrk rgbkrk 1.5K Dec 12 05:25 LICENSE
-rwxrwxr-x 1 rgbkrk rgbkrk 6.1M Dec 12 05:27 peekaboo          <--- Cleaned
-rwxrwxr-x 1 rgbkrk rgbkrk 8.2M Dec 12 05:27 peekaboo.default  <--- Original
-rw-rw-r-- 1 rgbkrk rgbkrk 5.8K Dec 12 05:25 peekaboo.go
-rw-rw-r-- 1 rgbkrk rgbkrk 1.6K Dec 12 05:30 README.md