Authentication was added in etcd 2.1. The etcd v3 API slightly modified the authentication feature's API and user interface to better fit the new data model. This guide is intended to help users set up basic authentication and role-based access control in etcd v3.
There is one special user,
root, and one special role,
rootuser, which has full access to etcd, must be created before activating authentication. The idea behind the
rootuser is for administrative purposes: managing roles and ordinary users. The
rootuser must have the
rootrole and is allowed to change anything inside etcd.
rootmay be granted to any user, in addition to the root user. A user with the
rootrole has both global read-write access and permission to update the cluster's authentication configuration. Furthermore, the
rootrole grants privileges for general cluster maintenance, including modifying cluster membership, defragmenting the store, and taking snapshots.
etcdctlhandles all things having to do with user accounts.
A listing of users can be found with:
$ etcdctl user list
Creating a user is as easy as
$ etcdctl user add myusername
Creating a new user will prompt for a new password. The password can be supplied from standard input when an option
Roles can be granted and revoked for a user with:
$ etcdctl user grant-role myusername foo
$ etcdctl user revoke-role myusername bar
The user's settings can be inspected with:
$ etcdctl user get myusername
And the password for a user can be changed with
$ etcdctl user passwd myusername
Changing the password will prompt again for a new password. The password can be supplied from standard input when an option
Delete an account with:
$ etcdctl user delete myusername
etcdctlhandles all things having to do with access controls for particular roles, as were granted to individual users.
List roles with:
$ etcdctl role list
Create a new role with:
$ etcdctl role add myrolename
A role has no password; it merely defines a new set of access rights.
Roles are granted access to a single key or a range of keys.
The range can be specified as an interval [start-key, end-key) where start-key should be lexically less than end-key in an alphabetical manner.
Access can be granted as either read, write, or both, as in the following examples:
# Give read access to a key /foo
$ etcdctl role grant-permission myrolename read /foo
# Give read access to keys with a prefix /foo/. The prefix is equal to the range [/foo/, /foo0)
$ etcdctl role grant-permission myrolename --prefix=true read /foo/
# Give write-only access to the key at /foo/bar
$ etcdctl role grant-permission myrolename write /foo/bar
# Give full access to keys in a range of [key1, key5)
$ etcdctl role grant-permission myrolename readwrite key1 key5
# Give full access to keys with a prefix /pub/
$ etcdctl role grant-permission myrolename --prefix=true readwrite /pub/
To see what's granted, we can look at the role at any time:
$ etcdctl role get myrolename
Revocation of permissions is done the same logical way:
$ etcdctl role revoke-permission myrolename /foo/bar
As is removing a role entirely:
$ etcdctl role remove myrolename
The minimal steps to enabling auth are as follows. The administrator can set up users and roles before or after enabling authentication, as a matter of preference.
Make sure the root user is created:
$ etcdctl user add root
Password of root:
$ etcdctl auth enable
After this, etcd is running with authentication enabled. To disable it for any reason, use the reciprocal command:
$ etcdctl --user root:rootpw auth disable
etcdctlsupports a similar flag as
$ etcdctl --user user:password get foo
The password can be taken from a prompt:
$ etcdctl --user user get foo
etcdctlcommands remain the same. Users and roles can still be created and modified, but require authentication by a user with the root role.
If an etcd server is launched with the option
--client-cert-auth=true, the field of Common Name (CN) in the client's TLS cert will be used as an etcd user. In this case, the common name authenticates the user and the client does not need a password.