List of model configuration keys¶

This document gives a list of all the configuration keys that can be applied to a Juju model.

agent-metadata-url¶

URL of private stream.

Default value: ""

Type: string

agent-stream¶

Version of Juju to use for deploy/upgrades.

Default value: released

Type: string

Description:

The agent-stream key specifies the “stream” to use when a Juju agent is to be installed or upgraded. This setting reflects the general stability of the software and defaults to ‘released’, indicating that only the latest stable version is to be used.

To run the upcoming stable release (before it has passed the normal QA process) you can set:

agent-stream: proposed

For testing purposes, you can use the latest unstable version by setting:

agent-stream: devel

The agent-version option specifies a “patch version” for the agent that is to be installed on a new controller relative to the Juju client’s current major.minor version (Juju uses a major.minor.patch numbering scheme).

For example, Juju 3.6.2 means major version 3, minor version 6, and patch version 2. On a client system with this release of Juju installed, the machine agent’s version for a newly-created controller would be the same. To specify a patch version of 1 (instead of 2), the following would be run:

juju bootstrap aws --agent-version='3.6.1'

If a patch version is available that is greater than that of the client then it can be targeted in this way:

juju bootstrap aws --auto-upgrade

agent-version¶

Note: This value is set by Juju.

The desired Juju agent version to use.

Default value: ""

Type: string

apt-ftp-proxy¶

The APT FTP proxy for the model.

Default value: ""

Type: string

apt-http-proxy¶

The APT HTTP proxy for the model.

Default value: ""

Type: string

apt-https-proxy¶

The APT HTTPS proxy for the model.

Default value: ""

Type: string

apt-mirror¶

The APT mirror for the model.

Default value: ""

Type: string

Description:

The APT packaging system is used to install and upgrade software on machines provisioned in the model, and many charms also use APT to install software for the applications they deploy. It is possible to set a specific mirror for the APT packages to use, by setting ‘apt-mirror’:

juju model-config apt-mirror=http://archive.ubuntu.com/ubuntu/

To restore the default behaviour you would run:

juju model-config --reset apt-mirror

The apt-mirror option is often used to point to a local mirror.

apt-no-proxy¶

List of domain addresses not to be proxied for APT (comma-separated).

Default value: ""

Type: string

automatically-retry-hooks¶

Determines whether the uniter should automatically retry failed hooks.

Default value: true

Type: bool

Description:

Juju retries failed hooks automatically using an exponential backoff algorithm. They will be retried after 5, 10, 20, 40 seconds up to a period of 5 minutes, and then every 5 minutes. The logic behind this is that some hook errors are caused by timing issues or the temporary unavailability of other applications - automatic retry enables the Juju model to heal itself without troubling the user.

However, in some circumstances, such as debugging charms, this behaviour can be distracting and unwelcome. For this reason, it is possible to set the automatically-retry-hooks option to ‘false’ to disable this behaviour. In this case, users will have to manually retry any hook which fails, using the command above, as with earlier versions of Juju.

Even with the automatic retry enabled, it is still possible to use retry manually using:

juju resolved unit-name/#

backup-dir¶

Directory used to store the backup working directory.

Default value: ""

Type: string

charmhub-url¶

The url for CharmHub API calls.

Default value: https://api.charmhub.io

Type: string

cloudinit-userdata¶

Cloud-init user-data (in yaml format) to be added to userdata for new machines created in this model.

Default value: ""

Type: string

Description:

The cloudinit-userdata allows the user to provide additional cloudinit data to be included in the cloudinit data created by Juju.

Specifying a key will overwrite what juju puts in the cloudinit file with the following caveats:

users and bootcmd keys will cause an error
The packages key will be appended to the packages listed by juju
The runcmds key will cause an error. You can specify preruncmd and postruncmd keys to prepend and append the runcmd created by Juju.

Use cases

setting a default locale for deployments that wish to use their own locale settings
adding custom CA certificates for models that are sitting behind an HTTPS proxy
adding a private apt mirror to enable private packages to be installed
add SSH fingerprints to a deny list to prevent them from being printed to the console for security-focused deployments

Background

Juju uses cloud-init to customise instances once they have been provisioned by the cloud. The cloudinit-userdata model configuration setting (model config) allows you to tweak what happens to machines when they are created up via the “user data” feature.

From the website:

Cloud images are operating system templates and every instance starts out as an identical clone of every other instance. It is the user data that gives every cloud instance its personality and cloud-init is the tool that applies user data to your instances automatically.

How to provide custom user data to cloudinit

Create a file, cloudinit-userdata.yaml, which starts with the cloudinit-userdata key and data you wish to include in the cloudinit file. Note: juju reads the value as a string, though formatted as YAML.

Template cloudinit-userdata.yaml:

cloudinit-userdata: |
	<key>: <value>
	<key>: <value>

Provide the path your file to the model-config command:

juju model-config --file cloudinit-userdata.yaml

How to read the current setting

To read the current value, provide the cloudinit-userdata key to the model-config command as a command-line parameter. Adding the –format yaml option ensures that it is properly formatted.

juju model-config cloudinit-userdata --format yaml

Sample output:

cloudinit-userdata: |
  packages:
	- 'python-keystoneclient'
	- 'python-glanceclient'

How to clear the current custom user data

Use the –reset option to the model-config command to clear anything that has been previously set.

juju model-config --reset cloudinit-userdata

Known issues

custom cloudinit-userdata must be passed via file, not as options on the command line (like the config command)

container-image-metadata-defaults-disabled¶

Whether default simplestreams sources are used for image metadata with containers.

Default value: false

Type: bool

container-image-metadata-url¶

The URL at which the metadata used to locate container OS image ids is located.

Default value: ""

Type: string

container-image-stream¶

The simplestreams stream used to identify which image ids to search when starting a container.

Default value: released

Type: string

container-inherit-properties¶

List of properties to be copied from the host machine to new containers created in this model (comma-separated).

Default value: ""

Type: string

Description:

The container-inherit-properties key allows for a limited set of parameters enabled on a Juju machine to be inherited by any hosted containers (KVM guests or LXD containers). The machine and container must be running the same series.

This key is only supported by the MAAS provider.

The parameters are:

apt-primary
apt-security
apt-sources
ca-certs

For MAAS v.2.5 or greater the parameters are:

apt-sources
ca-certs

For example:

juju model-config container-inherit-properties="ca-certs, apt-sources"

container-networking-method¶

Method of container networking setup - one of “provider”, “local”, or “” (auto-configure).

Default value: ""

Type: string

default-base¶

The default base image to use for deploying charms, will act like –base when deploying charms.

Default value: ""

Type: string

default-space¶

The default network space used for application endpoints in this model.

Default value: ""

Type: string

development¶

Whether the model is in development mode.

Default value: false

Type: bool

disable-network-management¶

Whether the provider should control networks (on MAAS models, set to true for MAAS to control networks.

Default value: false

Type: bool

Description:

This key can only be used with MAAS models and should otherwise be set to ‘false’ (default) unless you want to take over network control from Juju because you have unique and well-defined needs. Setting this to ‘true’ with MAAS gives you the same behaviour with containers as you already have with other providers: one machine-local address on a single network interface, bridged to the default bridge.

disable-telemetry¶

Disable telemetry reporting of model information.

Default value: false

Type: bool

egress-subnets¶

Source address(es) for traffic originating from this model.

Default value: ""

Type: string

enable-os-refresh-update¶

Whether newly provisioned instances should run their respective OS’s update capability.

Default value: true

Type: bool

Description:

When Juju provisions a machine, its default behaviour is to upgrade existing packages to their latest version. If your OS images are fresh and/or your deployed applications do not require the latest package versions, you can disable upgrades in order to provision machines faster.

Two boolean configuration options are available to disable APT updates and upgrades: enable-os-refresh-update (apt update) and enable-os-upgrade (apt upgrade), respectively.

enable-os-refresh-update: false
enable-os-upgrade: false

You may also want to just update the package list to ensure a charm has the latest software available to it by disabling upgrades but enabling updates.

enable-os-upgrade¶

Whether newly provisioned instances should run their respective OS’s upgrade capability.

Default value: true

Type: bool

Description:

Two Boolean configuration options are available to disable APT updates and upgrades: enable-os-refresh-update (apt update) and enable-os-upgrade (apt upgrade), respectively.

enable-os-refresh-update: false
enable-os-upgrade: false

You may also want to just update the package list to ensure a charm has the latest software available to it by disabling upgrades but enabling updates.

extra-info¶

Arbitrary user specified string data that is stored against the model.

Default value: ""

Type: string

firewall-mode¶

Note: This value cannot be changed after model creation.

The mode to use for network firewalling.

Default value: instance

Type: string

Valid values: instance, global, none

Description:

‘instance’ requests the use of an individual firewall per instance.
‘global’ uses a single firewall for all instances (access for a network port is enabled to one instance if any instance requires that port).
‘none’ requests that no firewalling should be performed inside the model. It’s useful for clouds without support for either global or per instance security groups.

image-stream¶

The simplestreams stream used to identify which image ids to search when starting an instance.

Default value: released

The logging config can be set to a (list of semicolon-separated) <filter>=<verbosity level> pairs, where <filter> can be any of the following:

<root> - matches all machine agent logs
unit - matches all unit agent logs
a module name, e.g. juju.worker.apiserver A module represents a single component of Juju, e.g. a worker. Generally, modules correspond one-to-one with Go packages in the Juju source tree. The module name is the value passed to loggo.GetLogger or loggo.GetLoggerWithLabels.

Modules have a nested tree structure - for example, the juju.api module includes submodules juju.api.application, juju.api.cloud, etc. <root> is the root of this module tree.
a label, e.g. #charmhub Labels cut across the module tree, grouping various modules which deal with a certain feature or information flow. For example, the #charmhub label includes all modules involved in making a request to Charmhub.

The currently supported labels are:

Label	Description
`#http`	HTTP requests
`#metrics`	Metric outputs - use as a fallback when Prometheus isn’t available
`#charmhub`	Charmhub client and callers.
`#cmr`	Cross model relations
`#cmr-auth`	Authentication for cross model relations
`#secrets`	Juju secrets

and where can be, in decreasing order of severity:

Level	Description
`CRITICAL`	Indicates a severe failure which could bring down the system.
`ERROR`	Indicates failure to complete a routine operation.
`WARNING`	Indicates something is not as expected, but this is not necessarily going to cause an error.
`INFO`	A regular log message intended for the user.
`DEBUG`	Information intended to assist developers in debugging.
`TRACE`	The lowest level - includes the full details of input args, return values, HTTP requests sent/received, etc.

When you set logging-config to module=level, then Juju saves that module’s logs for the given severity level and above. For example, setting logging-config to juju.worker.uniter=WARNING will capture all CRITICAL, ERROR and WARNING logs for the uniter, but discard logs for lower severity levels (INFO, DEBUG, TRACE).

Examples:

To collect debug logs for the dbaccessor worker:

juju model-config -m controller logging-config="juju.worker.dbaccessor=DEBUG"

To collect debug logs for the mysql/0 unit:

juju model-config -m foo logging-config="unit.mysql/0=DEBUG"

To collect trace logs for Charmhub requests:

juju model-config -m controller logging-config="#charmhub=TRACE"

To see what API requests are being made:

juju model-config -m controller logging-config="juju.apiserver=DEBUG"

To view details about each API request:

juju model-config -m controller logging-config="juju.apiserver=TRACE"

lxd-snap-channel¶

The channel to use when installing LXD from a snap (cosmic and later).

Default value: 5.0/stable

Type: string

max-action-results-age¶

The maximum age for action entries before they are pruned, in human-readable time format.

Default value: 336h

Type: string

max-action-results-size¶

The maximum size for the action collection, in human-readable memory format.

Default value: 5G

Type: string

mode¶

Mode is a comma-separated list which sets the mode the model should run in. So far only one is implemented

If ‘requires-prompts’ is present, clients will ask for confirmation before removing potentially valuable resources. (default “”).

Default value: requires-prompts

Type: string

name¶

Note: This value cannot be changed after model creation.

Note: This value must be set.

Description:

Juju keeps state on the running model and it can harvest (remove) machines which it deems are no longer required. This can help reduce running costs and keep the model tidy. Harvesting is guided by what “harvesting mode” has been set.

A Juju machine can be in one of four states:

Alive: The machine is running and being used.
Dying: The machine is in the process of being terminated by Juju, but hasn’t yet finished.
Dead: The machine has been successfully brought down by Juju, but is still being tracked for removal.
Unknown: The machine exists, but Juju knows nothing about it.

Juju can be in one of several harvesting modes, in order of most conservative to most aggressive:

none: Machines will never be harvested. This is a good choice if machines are managed via a process outside of Juju.
destroyed: Machines will be harvested if i) Juju “knows” about them and

ii) they are ‘Dead’. - unknown: Machines will be harvested if Juju does not “know” about them (‘Unknown’ state). Use with caution in a mixed environment or one which may contain multiple instances of Juju. - all: Machines will be harvested if Juju considers them to be ‘destroyed’ or ‘unknown’.

The default mode is destroyed.

Below, the harvest mode key for the current model is set to ‘none’:

juju model-config provisioner-harvest-mode=none

Default value: ""

Type: string

update-status-hook-interval¶

How often to run the charm update-status hook, in human-readable time format (default 5m, range 1-60m).

Default value: 5m

Type: string

uuid¶

Note: This value is set by Juju.

The UUID of the model.

Default value: ""

Type: string