1---
2title: Role-based access control
3---
4
5## Overview
6
7Authentication 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.
8
9## Special users and roles
10
11There is one special user, `root`, and one special role, `root`.
12
13### User `root`
14
15The `root` user, which has full access to etcd, must be created before activating authentication. The idea behind the `root` user is for administrative purposes: managing roles and ordinary users. The `root` user must have the `root` role and is allowed to change anything inside etcd.
16
17### Role `root`
18
19The role `root` may be granted to any user, in addition to the root user. A user with the `root` role has both global read-write access and permission to update the cluster's authentication configuration. Furthermore, the `root` role grants privileges for general cluster maintenance, including modifying cluster membership, defragmenting the store, and taking snapshots.
20
21## Working with users
22
23The `user` subcommand for `etcdctl` handles all things having to do with user accounts.
24
25A listing of users can be found with:
26
27```
28$ etcdctl user list
29```
30
31Creating a user is as easy as
32
33```
34$ etcdctl user add myusername
35```
36
37Creating a new user will prompt for a new password. The password can be supplied from standard input when an option `--interactive=false` is given. `--new-user-password` can also be used for supplying the password.
38
39Roles can be granted and revoked for a user with:
40
41```
42$ etcdctl user grant-role myusername foo
43$ etcdctl user revoke-role myusername bar
44```
45
46The user's settings can be inspected with:
47
48```
49$ etcdctl user get myusername
50```
51
52And the password for a user can be changed with
53
54```
55$ etcdctl user passwd myusername
56```
57
58Changing the password will prompt again for a new password. The password can be supplied from standard input when an option `--interactive=false` is given.
59
60Delete an account with:
61```
62$ etcdctl user delete myusername
63```
64
65
66## Working with roles
67
68The `role` subcommand for `etcdctl` handles all things having to do with access controls for particular roles, as were granted to individual users.
69
70List roles with:
71
72```
73$ etcdctl role list
74```
75
76Create a new role with:
77
78```
79$ etcdctl role add myrolename
80```
81
82A role has no password; it merely defines a new set of access rights.
83
84Roles are granted access to a single key or a range of keys.
85
86The 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.
87
88Access can be granted as either read, write, or both, as in the following examples:
89
90```
91# Give read access to a key /foo
92$ etcdctl role grant-permission myrolename read /foo
93
94# Give read access to keys with a prefix /foo/. The prefix is equal to the range [/foo/, /foo0)
95$ etcdctl role grant-permission myrolename --prefix=true read /foo/
96
97# Give write-only access to the key at /foo/bar
98$ etcdctl role grant-permission myrolename write /foo/bar
99
100# Give full access to keys in a range of [key1, key5)
101$ etcdctl role grant-permission myrolename readwrite key1 key5
102
103# Give full access to keys with a prefix /pub/
104$ etcdctl role grant-permission myrolename --prefix=true readwrite /pub/
105```
106
107To see what's granted, we can look at the role at any time:
108
109```
110$ etcdctl role get myrolename
111```
112
113Revocation of permissions is done the same logical way:
114
115```
116$ etcdctl role revoke-permission myrolename /foo/bar
117```
118
119As is removing a role entirely:
120
121```
122$ etcdctl role remove myrolename
123```
124
125## Enabling authentication
126
127The 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.
128
129Make sure the root user is created:
130
131```
132$ etcdctl user add root
133Password of root:
134```
135
136Enable authentication:
137
138```
139$ etcdctl auth enable
140```
141
142After this, etcd is running with authentication enabled. To disable it for any reason, use the reciprocal command:
143
144```
145$ etcdctl --user root:rootpw auth disable
146```
147
148## Using `etcdctl` to authenticate
149
150`etcdctl` supports a similar flag as `curl` for authentication.
151
152```
153$ etcdctl --user user:password get foo
154```
155
156The password can be taken from a prompt:
157
158```
159$ etcdctl --user user get foo
160```
161
162The password can also be taken from a command line flag `--password`:
163
164```
165$ etcdctl --user user --password password get foo
166```
167
168
169Otherwise, all `etcdctl` commands remain the same. Users and roles can still be created and modified, but require authentication by a user with the root role.
170
171## Using TLS Common Name
172As of version v3.2 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. Note that if both of 1. `--client-cert-auth=true` is passed and CN is provided by the client, and 2. username and password are provided by the client, the username and password based authentication is prioritized. Note that this feature cannot be used with gRPC-proxy and gRPC-gateway. This is because gRPC-proxy terminates TLS from its client so all the clients share a cert of the proxy. gRPC-gateway uses a TLS connection internally for transforming HTTP request to gRPC request so it shares the same limitation. Therefore the clients cannot provide their CN to the server correctly. gRPC-proxy will cause an error and stop if a given cert has non empty CN. gRPC-proxy returns an error which indicates that the client has an non empty CN in its cert.
173
174As of version v3.3 if an etcd server is launched with the option `--peer-cert-allowed-cn` filtering of CN inter-peer connections is enabled.  Nodes can only join the etcd cluster if their CN match the allowed one.
175See [etcd security page](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/security.md) for more details.
176
177