Detailed description of a few selected arguments

This list is not the full list, but a few arguments that where chosen.

admin-access

admin-access controls the CIDR which can access the admin endpoints (SSH to each node, HTTPS to the master).

If not specified, no IP level restrictions will apply (though there are still restrictions, for example you need a permitted SSH key to access the SSH service!).

Examples:

CLI:

--admin-access=18.0.0.0/8 to restrict to IPs in the 18.0.0.0/8 CIDR

--admin-access=18.0.0.0/8 --admin-access=19.0.0.0/8 to restrict to IPs in the 18.0.0.0/8 and 19.0.0.0/8 CIDR blocks

YAML:

See the docs in ../cluster_spec.md#adminaccess

dns-zone

dns-zone controls the Route53 hosted zone in which DNS records will be created. It can either by the name of the hosted zone (example.com), or it can be the ID of the hosted zone (Z1GABCD1ABC2DEF)

Suppose you are creating a cluster named "dev.kubernetes.example.com`:

  • You can specify a --dns-zone=example.com (you can have subdomains in a hosted zone)
  • You could also use --dns-zone=kubernetes.example.com

You do have to set up the DNS nameservers so your hosted zone resolves. kops used to create the hosted zone for you, but now (as you have to set up the nameservers anyway), there doesn't seem much reason to do so!

If you don't specify a dns-zone, kops will list all your hosted zones, and choose the longest that is a suffix of your cluster name. So for dev.kubernetes.example.com, if you have kubernetes.example.com, example.com and somethingelse.example.com, it would choose kubernetes.example.com. example.com matches but is shorter; somethingelse.example.com is not a suffix-match.

Examples:

--dns-zone=example.com to use the hosted zone with a name of example.com

cloud-labels

cloud-labels specifies tags for instance groups in AWS. The supported format is a CSV list of key=value pairs. Keys and values must not contain embedded commas but they may contain equals signs ('=') as long as the field is quoted:

  • --cloud-labels "Project=\"Name=Foo Customer=Acme\",Owner=Jane Doe" will be parsed as {Project:"Name=Foo Customer=Acme", Owner: "Jane Doe"}

UpdatePolicy

Cluster.Spec.UpdatePolicy

Values:

  • external updates are performed by an external system (or manually), should not be automatically applied

  • unset means to use the default policy, which is currently to apply OS security updates unless they require a reboot

Required packages are also updated during bootstrapping if the value is not set.

out

out determines the directory into which Kops will write the target output for Terraform and CloudFormation. It defaults to out/terraform and out/cloudformation respectively.

API only Arguments

Certain arguments can only be passed via the API, eg, kops edit cluster. The following documents some of the more interesting or lesser-known options. See the Cluster Spec page for more fields.

kubeletPreferredAddressTypes

The apiserver can now select which type of kubelet-reported address to use for apiserver->node communications, using the --kubelet-preferred-address-types flag. (https://github.com/kubernetes/kubernetes/pull/35497, @liggitt)

Example:

kubeAPIServer:
    kubeletPreferredAddressTypes:
    - InternalIP
    - ExternalIP

More information about using YAML is available here.