Working with multiple users
Juju has an internal user framework that allows for the sharing of controllers and models. To achieve this, a Juju user can be created, disabled, and have rights granted and revoked. Users remote to the system that created a controller can use their own Juju client to log in to the controller and manage the environment based on the rights conferred. Multiple users can be accommodated by the same Juju client.
Various categories of users can be defined based on the permissions they have been granted. In turn, these permissions lead to certain abilities. See page User types and abilities for an overview.
Juju users are not related in any way to the client system users.
There are two ways users are introduced into Juju:
- with the
bootstrapcommand, which creates the initial controller administrator
- with the
add-usercommand, which creates a generic user
In the second case the user gets a password set up but in the first case the user is left without one. This is why if such an admin tries to log out (
logout) before creating a password the command will fail and a warning will be emitted. An admin should, therefore, create a password once the controller is created:
juju bootstrap aws juju change-user-password
In a Juju context, the term “credential” is related to the accessing of a chosen backing cloud, and not to Juju users. See Credentials for guidance.
Creating a generic user
add-user command is used, a string of text is produced that encodes information about the user and the controller. This string is supplied to the intended operator who will use it to register the controller using their own Juju client.
The user will be asked to enter an arbitrary (but hopefully meaningful) name to the controller as well as create a password for themselves. The controller name needs to be unique within the context of the client. The user’s password is stored on the controller.
Controller registration (and any other Juju operations that involves communication between a client and a controller) necessitates the client be able to contact the controller over the network on TCP port 17070. In particular, if using a LXD-based cloud, network routes need to be in place (i.e. to contact the controller LXD container the client traffic must be routed through the LXD host).
To create user ‘mat’ a controller administrator uses the
juju add-user mat
This will produce output similar to:
User "mat" added Please send this command to mat: juju register ME0TA21hdDAWExQxMC4xNDkuMTMzLjIwOToxNzA3MAQg7D-RDR8cnioqd7ctEoCjyDzaprK4wXodvfMBBrgBUKETDGx4ZC1iaW9uaWMtMQAA "mat" has not been granted access to any models. You can use "juju grant" to grant access.
An administrator provides the command (manually) to the intended operator, who will execute it:
juju register ME0TA21hdDAWExQxMC4xNDkuMTMzLjIwOToxNzA3MAQg7D-RDR8cnioqd7ctEoCjyDzaprK4wXodvfMBBrgBUKETDGx4ZC1iaW9uaWMtMQAA
Sample user session:
Enter a new password: Confirm password: Enter a name for this controller [lxd-bionic-1]: lxd-bionic-1 Initial password successfully set for mat. Welcome, mat. You are now logged into "lxd-bionic-1". There are no models available. You can add models with "juju add-model", or you can ask an administrator or owner of a model to grant access to that model with "juju grant".
The name of the original controller, in this case ‘lxd-bionic-1’, is offered as a default controller name.
A user can be acted upon (e.g. granted permissions) prior to that user registering the controller.
Logins and logouts
A user who has just registered a controller is automatically logged in to that controller.
A user can log out at any time:
To log in to a controller, the operator needs to specify both the user and the controller:
juju login -u mat -c lxd-bionic-1
The following is a quick way to determine the current user (as well as the current controller and model):
Controller: lxd-bionic-1 Model: <no-current-model> User: mat
See Controller logins for more information.
Disabling and re-enabling users
To immediately sever a user’s communication with their controller the
disable-user command is employed. To re-establish communication the
enable-user command is used.
To disable the user ‘mike’:
juju disable-user mike
juju enable-user mike
Disabled users are suppressed in the output to the
users command unless the
--all option is used, whereby the output will show “disabled”:
Controller: cstack Name Display name Access Date created Last connection admin* admin superuser 2018-12-12 just now mike login 17 minutes ago never connected (disabled)
Changing user passwords
A user is prompted to set a password when registering a controller. This password can subsequently be changed either by the user himself or by a controller admin. For the user, it is simply a matter of running:
The admin user supplies the name of the user whose password is to be changed:
juju change-user-password mike
Then simply follow the prompts to enter and confirm a new password.
Re-generating a lost registration string
If the original registering token fails to work or is lost a new token can be generated by a controller admin. This is done through the use of the
--reset option in conjunction with the
change-user-password command. For example, to generate a new token for ‘jon’:
juju change-user-password jon --reset
The previous token will be invalidated, and the user should register with the new token.
Managing models in a multi-user context
In this section we go over the various ways models can be managed in a multi-user context. Subtopics include:
- Providing model ownership during model creation
- Model access
- Controller access
- Cloud access (
Providing model ownership during model creation
The model creator becomes, by default, the model owner. However, the creation process does allow for owner designation. To add model ‘staging’ and designate user ‘neo’ as the owner:
juju add-model --owner=neo staging
See the Adding a model page for the basics on adding models.
A controller admin uses the
grant command to give a user ‘read’, ‘write’, or ‘admin’ access to a model:
read: A user can view the state of a model (e.g.
write: In addition to ‘read’ abilities, a user can modify/configure models (e.g.
admin: In addition to ‘write’ abilities, a user can perform model upgrades (
upgrade-model) and connect to machines via
juju ssh. Makes the user an effective model owner. See Machine authentication for how to connect to machines.
Here we give ‘bob’ write access to model ‘genesis’:
juju grant bob write genesis
Current model access for a user can be viewed by specifying the user with the
models command. Here we inspect the access enjoyed by user ‘mat’:
juju models --user mat
Controller: lxd-bionic-1 Model Cloud/Region Status Access Last connection admin/euphoric* localhost/localhost available read never connected
Notice how the model name is prepended with the remote user’s name, which is the ‘owner’ of the model.
Access can be viewed on a per-model basis by using the
show-model command. Here we query model ‘mara’:
juju show-model mara
users: admin: display-name: admin access: admin last-connection: never connected jim: access: write last-connection: never connected pete: access: admin last-connection: never connected
A controller actually refers to a special kind of model that acts as the nucleus for each cloud environment. In addition to the three levels of model access, three further levels of access can be applied to a controller:
login: the standard access level, enabling a user to log in to a controller.
add-model: in addition to login access, a user can add and remove models.
superuser: makes a user an effective controller administrator.
The command syntax for controller access is the same as for model access, only without the need to specify a model. As usual, with no controller specified via the
-c option, the current controller is the assumed target.
Here we give ‘jim’ the ‘add-model’ permission:
juju grant jim add-model
Current controller access for all users registered to a controller can be viewed with the
users command. Example output:
Controller: azure-1 Name Display name Access Date created Last connection admin* admin superuser 2018-12-14 just now bob login 1 hour ago 50 minutes ago jim add-model 2018-12-14 58 minutes ago
In addition, a controller admin can use the
show-user command to get controller access on a per-user basis, in addition to other information on the user.
v.2.6.0, models from more than one cloud can be managed by a controller. The controller will naturally manage the cloud that hosts the controller itself but afterwards other clouds can be added. With such a design it is natural to want to manage user access on a per-cloud basis. This is done with the
revoke command is used by a controller administrator to demote a user’s access to the next lowest level. That is, if a user has ‘write’ access to a model and ‘read’ is revoked then both ‘read’ and ‘write’ are removed. This works similarly for controller access. If a user has ‘superuser’ access and ‘add-model’ is revoked then both ‘add-model’ and ‘superuser’ are removed.
If user ‘bob’ has ‘write’ access to model ‘gotcha’, use the following to remove all access to this model:
juju revoke bob read gotcha
Confirm this action with
juju models --user bob.
If user ‘jim’ has ‘superuser’ access to controller ‘waves’, use the following to leave the user with just ‘login’ access:
juju revoke -c waves jim add-model
Confirm this action with
juju show-user --user jim.
As usual, if a controller is not specified (
-c) the default controller is the currently active one.
To explore using Juju with multiple users consider the following tutorials: