dcos

Example configs for DC/OS

For more information see our DC/OS Getting Started Guide.

Deploy webapp

dcos marathon app add webapp.json

Deploy linkerd

Note the linkerd-dcos.json files assume 4 nodes. Modify this to equal the total number of public+private nodes in your cluster.

Note that the simple-proxy/linkerd-dcos.json is one of many ways you can setup Linkerd to run in DC/OS. Unfortunately using linkerd-dcos.json might make it difficult to send operating system signals to Linkerd e.g. SIGTERM for graceful shutdown. An alternative is one way to set up Linkerd so that it can catch os signals. This application definition uses the fetch API available in DC/OS 1.10. You can use a top-level uri list for DC/OS <= 1.9.

Multiple linkerd configurations are described below. Pick the one that's most appropriate for your setup. When testing configurations, be sure to set the PUBLIC_NODE env variable to the external address of the public node in your cluster.

linkerd simple proxy

To deploy the most basic configuration, with linkerd as a proxy running on port 4140 for inbound requests, run:

dcos marathon app add simple-proxy/linkerd-dcos.json

Test this configuration with:

$ http_proxy=$PUBLIC_NODE:4140 curl -s http://webapp/hello
Hello world

linkerd ingress configuration

To deploy linkerd with an ingress router running on port 4142 and an internal router running on port 4140, run:

dcos marathon app add ingress/linkerd-dcos.json

Test this configuration with:

$ curl $PUBLIC_NODE:4242/hello
Hello world

linkerd in linker-to-linker mode

To deploy linkerd in linker-to-linker mode, with outgoing traffic served on a router running on port 4140, and incoming traffic served on a router running on port 4141, run:

dcos marathon app add linker-to-linker/linkerd-dcos.json

Test this configuration with:

$ http_proxy=$PUBLIC_NODE:4140 curl -s http://webapp/hello
Hello world

linkerd with Strict Mode and Marathon Authentication

DC/OS Supports increased security modes. Specifically, with Strict mode, all Marathon access is via TLS. Additionally, Mesosphere Enterprise DC/OS defaults to requiring authenticated access to Marathon. This example demonstrates configuring a linkerd's Marathon Namer for both Strict mode and Marathon Authentication.

Strict mode

To enable linkerd's Marathon namer for Strict mode, linkerd-marathon-auth/linkerd-config.yml includes the following io.l5d.marathon config block:

namers:
- kind: io.l5d.marathon
  host: leader.mesos
  port: 443
  prefix: "/io.l5d.marathon"
  uriPrefix: "/marathon"
  tls:
    disableValidation: false
    commonName: master.mesos
    trustCerts:
      - /mnt/mesos/sandbox/.ssl/ca.crt

Browse to the DC/OS Security page for more information on Strict mode.

Marathon Authentication

To configure linkerd to make authenticated requests to Marathon, create a keypair, service account, and DC/OS secret. Full instructions are documented in the DC/OS examples repo. Follow those instructions, stop at the Install linkerd step, as we're going to install our own linkerd rather than use the DC/OS Universe package.

We now specify the location of these credentials in linkerd-marathon-auth/linkerd-dcos.json:

"env": {
  "DCOS_SERVICE_ACCOUNT_CREDENTIAL": { "secret": "serviceCredential" }
},
"secrets": {
  "serviceCredential": {
    "source": "linkerd-secret"
  }
},

Deploying

With linkerd configured for Strict mode and Marathon Authentication, we're ready to deploy:

dcos marathon app add linkerd-marathon-auth/linkerd-dcos.json

Test this configuration with:

$ http_proxy=$PUBLIC_NODE:4140 curl -s http://webapp/hello
Hello world

linkerd with namerd

namerd

Start by deploying namerd:

dcos marathon app add namerd/namerd-dcos.json

Test the namerd configuration with:

$ curl $PUBLIC_NODE:4180/api/1/dtabs/default
[{"prefix":"/marathonId","dst":"/#/io.l5d.marathon"},{"prefix":"/svc","dst":"/$/io.buoyant.http.domainToPathPfx/marathonId"}]

linkerd

Next deploy linkerd configured to talk to namerd when routing requests:

dcos marathon app add linkerd-with-namerd/linkerd-dcos.json

Test this configuration with:

$ http_proxy=$PUBLIC_NODE:4140 curl -s http://webapp/hello
Hello world

linkerd with namerd in linker-to-linker mode

Deploy namerd as described in the previous section. Then deploy linkerd in linker-to-linker mode, configured to talk to namerd when routing requests:

dcos marathon app add linker-to-linker-with-namerd/linkerd-dcos.json

Test this configuration with:

$ http_proxy=$PUBLIC_NODE:4140 curl -s http://webapp/hello
Hello world

Application Groups

Marathon supports an "Application Group" concept, where applications are deployed and named using a hierarchical path-based naming structure. Because the linkerd config examples documented here all use the domainToPathPfx rewriting namer, marathon applications within a group are routed by reversing the group name into a domain-like name. For example, webgroup/webapp-a/webapp-a1 becomes webapp-a1.webapp-a.webgroup:

Webgroup

This example demonstrates linkerd routing requests to a Marathon app in an application group.

dcos marathon group add webgroup.json

http_proxy=$PUBLIC_NODE:4140 curl webapp-a1.webapp-a.webgroup/hello
Hello world

Hello World

This example demonstrates inter-service routing, along with a routing override.

Deploy 3 services: hello, world-v1, world-v2:

dcos marathon group add hello-world.json

Route requests linkerd -> hello -> linkerd -> world-v1:

http_proxy=$PUBLIC_NODE:4140 curl hello.hw.buoyant
Hello (10.0.3.80) world (10.0.1.148)!

Routing override from world-v1 to world-v2:

# 25% to world-v2
http_proxy=$PUBLIC_NODE:4140 curl -H 'l5d-dtab: /svc/world-v1.hw.buoyant => 3 * /marathonId/buoyant/hw/world-v1 & /marathonId/buoyant/hw/world-v2' hello.hw.buoyant
Hello (10.0.1.56) world (10.0.1.56)!!

# 75% to world-v2
http_proxy=$PUBLIC_NODE:4140 curl -H 'l5d-dtab: /svc/world-v1.hw.buoyant => /marathonId/buoyant/hw/world-v1 & 3 * /marathonId/buoyant/hw/world-v2' hello.hw.buoyant
Hello (10.0.1.56) earth (10.0.1.56)!!

# 100% to world-v2
http_proxy=$PUBLIC_NODE:4140 curl -H 'l5d-dtab: /svc/world-v1.hw.buoyant => /svc/world-v2.hw.buoyant' hello.hw.buoyant
Hello (10.0.1.56) earth (10.0.1.56)!!