Security considerations


Deis is not suitable for multi-tenant environments or hosting untrusted code.

A major goal of Deis is to be operationally secure and trusted by operations engineers in every deployed environment. There are, however, two notable security-related considerations to be aware of when deploying Deis.

Access to etcd

Since all Deis configuration settings are stored in etcd (including passwords, keys, etc.), any access to the etcd cluster compromises the security of the entire Deis installation. The various provision scripts configure the etcd daemon to only listen on the private network interface, but any host or container with access to the private network has full access to etcd. This also includes deployed application containers, which cannot be trusted.

The planned approach is to configure iptables on the machines to prevent unauthorized access from containers. Some requirements include:

  • Containers must be able to access the outside world
  • Containers must be able to access other containers
  • Containers cannot access the CoreOS host (SSH, etcd, etc)

Further discussion about this approach is appreciated in GitHub issue #986.

Application runtime segregation

Users of Deis often want to deploy their applications to separate environments (commonly: development, staging, and production). Typically, physical network isolation isn’t the goal, but rather segregation of application environments - if a development app goes haywire, it shouldn’t affect production applications that are running in the cluster.

In Deis, deployed applications can be segregated by using the `deis tags` command. This enables you to tag machines in your cluster with arbitrary metadata, then configure your applications to be scheduled to machines which match the metadata.

For example, if some machines in your cluster are tagged with `environment=production` and some with `environment=staging`, you can configure an application to be deployed to the production environment by using `deis tags set environment=production`. Deis will pass this configuration along to the scheduler, and your applications in different environments on running on separate hardware.

Running Deis on Public Clouds

If you are running on a public cloud without security group features, you will have to set up security groups yourself through either iptables or a similar tool. The only ports that should be exposed to the public are:

  • 22: for remote SSH
  • 80: for the routers
  • 443: (optional) routers w/ SSL enabled
  • 2222: for the builder

For providers that do not supply a security group feature, please try contrib/util/


If you need to add a new node to the cluster and you are using the custom firewall contrib/util/ you must allow the access to the cluster running the next command in each existing node:

$ NEW_NODE="IP address" contrib/util/

Router firewall

The Router component includes a firewall to help thwart attacks. It can be enabled by running: deisctl config router set firewall/enabled=true. For more information, see the router README and Customizing router.