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Using Flux
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fluxctl provides an API that can be used from the command line.

The --help for fluxctl is described below.

Installing fluxctl

Mac OS

If you are using a Mac and use Homebrew, you can simply run:

brew install fluxctl

Linux

Ubuntu (and others): snaps

Many Linux distributions support snaps these days, which makes it very easy to install fluxctl and stay up to date.

To install it, simply run:

sudo snap install fluxctl

If you would prefer to track builds from master, run

sudo snap install fluxctl --edge

instead.

Arch Linux

Install the fluxctl-bin package from the AUR:

git clone https://aur.archlinux.org/fluxctl-bin.git
cd fluxctl-bin
makepkg -si

Binary releases

With every release of Flux, we release binaries of fluxctl for Mac, Linux and Windows. Download them from the Flux release page.

Connecting fluxctl to the daemon

By default, fluxctl will attempt to port-forward to your Flux instance, assuming it runs in the "default" namespace. You can specify a different namespace with the --k8s-fwd-ns flag:

fluxctl --k8s-fwd-ns=weave list-workloads

The namespace can also be given in the environment variable FLUX_FORWARD_NAMESPACE:

export FLUX_FORWARD_NAMESPACE=weave
fluxctl list-workloads

If you are not able to use the port forward to connect, you will need some way of connecting to the Flux API directly (NodePort, LoadBalancer, VPN, etc). Be aware that exposing the Flux API in this way is a security hole, because it can be accessed without authentication.

Once that is set up, you can specify an API URL with --url or the environment variable FLUX_URL:

fluxctl --url http://127.0.0.1:3030/api/flux list-workloads

Flux API service

Now you can easily query the Flux API:

fluxctl list-workloads --all-namespaces

Add an SSH deploy key to the repository

Flux connects to the repository using an SSH key. You have two options:

1. Allow Flux to generate a key for you

If you don't specify a key to use, Flux will create one for you. Obtain the public key through fluxctl:

$ fluxctl identity
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQDCN2ECqUFMR413CURbLBcG41fLY75SfVZCd3LCsJBClVlEcMk4lwXxA3X4jowpv2v4Jw2qqiWKJepBf2UweBLmbWYicHc6yboj5o297//+ov0qGt/uRuexMN7WUx6c93VFGV7Pjd60Yilb6GSF8B39iEVq7GQUC1OZRgQnKZWLSQ==

Alternatively, you can see the public key in the flux log.

The public key will need to be given to the service hosting the Git repository. For example, in GitHub you would create an SSH deploy key in the repository, supplying that public key.

The flux logs should show that it has now connected to the repository and synchronised the cluster.

When using Kubernetes, this key is stored as a Kubernetes secret. You can restart flux and it will continue to use the same key.

2. Specify a key to use

Create a Kubernetes Secret from a private key:

kubectl create secret generic flux-git-deploy --from-file=identity=/full/path/to/private_key

this will result in a secret that has the structure:

  apiVersion: v1
  data:
    identity: <base64 encoded RSA PRIVATE KEY>
  kind: Secret
  type: Opaque
  metadata:
    ...

Now add the secret to the flux-deployment.yaml manifest:

    ...
    spec:
      volumes:
      - name: git-key
        secret:
          secretName: flux-git-deploy

And add a volume mount for the container:

    ...
    spec:
      containers:
      - name: fluxd
        volumeMounts:
        - name: git-key
          mountPath: /etc/fluxd/ssh

You can customise the paths and names of the chosen key with the arguments (examples with defaults): --k8s-secret-name=flux-git-deploy, --k8s-secret-volume-mount-path=/etc/fluxd/ssh and --k8s-secret-data-key=identity

Using an SSH key allows you to maintain control of the repository. You can revoke permission for flux to access the repository at any time by removing the deploy key.

fluxctl helps you deploy your code.

Connecting:

  # To a fluxd running in namespace "default" in your current kubectl context
  fluxctl list-workloads

  # To a fluxd running in namespace "weave" in your current kubectl context
  fluxctl --k8s-fwd-ns=weave list-workloads

Workflow:
  fluxctl list-workloads                                                   # Which workloads are running?
  fluxctl list-images --workload=default:deployment/foo                    # Which images are running/available?
  fluxctl release --workload=default:deployment/foo --update-image=bar:v2  # Release new version.

Usage:
  fluxctl [command]

Available Commands:
  automate         Turn on automatic deployment for a workload.
  deautomate       Turn off automatic deployment for a workload.
  help             Help about any command
  identity         Display SSH public key
  list-workloads   List workloads currently running in the cluster.
  list-images      Show the deployed and available images.
  lock             Lock a workload, so it cannot be deployed.
  policy           Manage policies for a workload.
  release          Release a new version of a workload.
  save             save workload definitions to local files in cluster-native format
  sync             synchronize the cluster with the git repository, now
  unlock           Unlock a workload, so it can be deployed.
  version          Output the version of fluxctl

Flags:
  -h, --help                            help for fluxctl
      --k8s-fwd-labels stringToString   Labels used to select the fluxd pod a port forward should be created for. You can also set the environment variable FLUX_FORWARD_LABELS (default [app=flux])
      --k8s-fwd-ns string               Namespace in which fluxd is running, for creating a port forward to access the API. No port forward will be created if a URL or token is given. You can also set the environment variable FLUX_FORWARD_NAMESPACE (default "default")
  -t, --token string                    Weave Cloud authentication token; you can also set the environment variable WEAVE_CLOUD_TOKEN or FLUX_SERVICE_TOKEN
  -u, --url string                      Base URL of the Flux API (defaults to "https://cloud.weave.works/api/flux" if a token is provided); you can also set the environment variable FLUX_URL

Use "fluxctl [command] --help" for more information about a command.

Workloads

What is a Workload?

This term refers to any cluster resource responsible for the creation of containers from versioned images - in Kubernetes these are objects such as Deployments, DaemonSets, StatefulSets and CronJobs.

Viewing Workloads

The first thing to do is to check whether Flux can see any running workloads. To do this, use the list-workloads subcommand:

$ fluxctl list-workloads
WORKLOAD                       CONTAINER   IMAGE                                         RELEASE  POLICY
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld:master-a000001  ready
                               sidecar     quay.io/weaveworks/sidecar:master-a000002

Note that the actual images running will depend on your cluster.

Inspecting the Version of a Container

Once we have a list of workloads, we can begin to inspect which versions of the image are running.

$ fluxctl list-images --workload default:deployment/helloworld
WORKLOAD                       CONTAINER   IMAGE                          CREATED
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld
                                           |   master-9a16ff945b9e        20 Jul 16 13:19 UTC
                                           |   master-b31c617a0fe3        20 Jul 16 13:19 UTC
                                           |   master-a000002             12 Jul 16 17:17 UTC
                                           '-> master-a000001             12 Jul 16 17:16 UTC
                               sidecar     quay.io/weaveworks/sidecar
                                           '-> master-a000002             23 Aug 16 10:05 UTC
                                               master-a000001             23 Aug 16 09:53 UTC

The arrows will point to the version that is currently running alongside a list of other versions and their timestamps.

Releasing a Workload

We can now go ahead and update a workload with the release subcommand. This will check whether each workload needs to be updated, and if so, write the new configuration to the repository.

$ fluxctl release --workload=default:deployment/helloworld --user=phil --message="New version" --update-all-images
Submitting release ...
Commit pushed: 7dc025c
Applied 7dc025c61fdbbfc2c32f792ad61e6ff52cf0590a
WORKLOAD                     STATUS   UPDATES
default:deployment/helloworld  success  helloworld: quay.io/weaveworks/helloworld:master-a000001 -> master-9a16ff945b9e

$ fluxctl list-images --workload default:deployment/helloworld
WORKLOAD                       CONTAINER   IMAGE                          CREATED
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld
                                           '-> master-9a16ff945b9e        20 Jul 16 13:19 UTC
                                               master-b31c617a0fe3        20 Jul 16 13:19 UTC
                                               master-a000002             12 Jul 16 17:17 UTC
                                               master-a000001             12 Jul 16 17:16 UTC
                               sidecar     quay.io/weaveworks/sidecar
                                           '-> master-a000002             23 Aug 16 10:05 UTC
                                               master-a000001             23 Aug 16 09:53 UTC

Turning on Automation

Automation can be easily controlled from fluxctl with the automate subcommand.

$ fluxctl automate --workload=default:deployment/helloworld
Commit pushed: af4bf73
WORKLOAD                     STATUS   UPDATES
default:deployment/helloworld  success

$ fluxctl list-workloads --namespace=default
WORKLOAD                       CONTAINER   IMAGE                                             RELEASE  POLICY
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld:master-9a16ff945b9e ready    automated
                               sidecar     quay.io/weaveworks/sidecar:master-a000002

Automation can also be enabled by adding the annotation flux.weave.works/automated: "true" to the deployment.

We can see that the list-workloads subcommand reports that the helloworld application is automated. Flux will now automatically deploy a new version of a workload whenever one is available and commit the new configuration to the version control system.

Turning off Automation

Turning off automation is performed with the deautomate command:

$ fluxctl deautomate --workload=default:deployment/helloworld
Commit pushed: a54ef2c
WORKLOAD                     STATUS   UPDATES
default:deployment/helloworld  success

$ fluxctl list-workloads --namespace=default
WORKLOAD                       CONTAINER   IMAGE                                             RELEASE  POLICY
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld:master-9a16ff945b9e ready
                               sidecar     quay.io/weaveworks/sidecar:master-a000002

We can see that the workload is no longer automated.

Rolling back a Workload

Rolling back can be achieved by combining:

  • deautomate to prevent Flux from automatically updating to newer versions, and
  • release to deploy the version you want to roll back to.
$ fluxctl list-images --workload default:deployment/helloworld
WORKLOAD                       CONTAINER   IMAGE                          CREATED
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld
                                           '-> master-9a16ff945b9e        20 Jul 16 13:19 UTC
                                               master-b31c617a0fe3        20 Jul 16 13:19 UTC
                                               master-a000002             12 Jul 16 17:17 UTC
                                               master-a000001             12 Jul 16 17:16 UTC
                               sidecar     quay.io/weaveworks/sidecar
                                           '-> master-a000002             23 Aug 16 10:05 UTC
                                               master-a000001             23 Aug 16 09:53 UTC

$ fluxctl deautomate --workload=default:deployment/helloworld
Commit pushed: c07f317
WORKLOAD                       STATUS   UPDATES
default:deployment/helloworld  success

$ fluxctl release --workload=default:deployment/helloworld --update-image=quay.io/weaveworks/helloworld:master-a000001
Submitting release ...
Commit pushed: 33ce4e3
Applied 33ce4e38048f4b787c583e64505485a13c8a7836
WORKLOAD                     STATUS   UPDATES
default:deployment/helloworld  success  helloworld: quay.io/weaveworks/helloworld:master-9a16ff945b9e -> master-a000001

$ fluxctl list-images --workload default:deployment/helloworld
WORKLOAD                     CONTAINER   IMAGE                          CREATED
default:deployment/helloworld  helloworld  quay.io/weaveworks/helloworld
                                           |   master-9a16ff945b9e        20 Jul 16 13:19 UTC
                                           |   master-b31c617a0fe3        20 Jul 16 13:19 UTC
                                           |   master-a000002             12 Jul 16 17:17 UTC
                                           '-> master-a000001             12 Jul 16 17:16 UTC
                               sidecar     quay.io/weaveworks/sidecar
                                           '-> master-a000002             23 Aug 16 10:05 UTC
                                               master-a000001             23 Aug 16 09:53 UTC

Locking a Workload

Locking a workload will stop manual or automated releases to that workload. Changes made in the file will still be synced.

$ fluxctl lock --workload=deployment/helloworld
Commit pushed: d726722
WORKLOAD                       STATUS   UPDATES
default:deployment/helloworld  success

Releasing an image to a locked workload

It may be desirable to release an image to a locked workload while maintaining the lock afterwards. In order to not having to modify the lock policy (which includes author and reason), one may use --force:

fluxctl release --workload=default:deployment/helloworld --update-all-images --force

Unlocking a Workload

Unlocking a workload allows it to have manual or automated releases (again).

$ fluxctl unlock --workload=deployment/helloworld
Commit pushed: 708b63a
WORKLOAD                       STATUS   UPDATES
default:deployment/helloworld  success

Recording user and message with the triggered action

Issuing a deployment change results in a version control change/git commit, keeping the history of the actions. The Flux daemon can be started with several flags that impact the commit information:

flag purpose default
git-user committer name Weave Flux
git-email committer email [email protected]
git-set-author override the commit author false

Actions triggered by a user through the CLI fluxctl tool, can have the commit author information customized. This is handy for providing extra context in the notifications and history. Whether the customization is possible, depends on the Flux daemon (fluxd) git-set-author flag. If set, the commit author will be customized in the following way:

Image Tag Filtering

When building images it is often useful to tag build images by the branch that they were built against for example:

quay.io/weaveworks/helloworld:master-9a16ff945b9e

Indicates that the helloworld image was built against master commit 9a16ff945b9e.

When automation is turned on Flux will, by default, use whatever is the latest image on a given repository. If you want to only auto-update your image against a certain subset of tags then you can do that using tag filtering.

So for example, if you want to only update the "helloworld" image to tags that were built against the "prod" branch then you could do the following:

fluxctl policy --workload=default:deployment/helloworld --tag-all='prod-*'

If your pod contains multiple containers then you tag each container individually:

fluxctl policy --workload=default:deployment/helloworld --tag='helloworld=prod-*' --tag='sidecar=prod-*'

Manual releases without explicit mention of the target image will also adhere to tag filters. This will only release the newest image matching the tag filter:

fluxctl release --workload=default:deployment/helloworld --update-all-images

To release an image outside of tag filters, either specify the image:

fluxctl release --workload=default:deployment/helloworld --update-image=helloworld:dev-abc123

or use --force:

fluxctl release --workload=default:deployment/helloworld --update-all-images --force

Please note that automation might immediately undo this.

Filter pattern types

Flux currently offers support for glob, semver and regexp based filtering.

Glob

The glob (*) filter is the simplest filter Flux supports, a filter can contain multiple globs:

fluxctl policy --workload=default:deployment/helloworld --tag-all='glob:master-v1.*.*'

Semver

If your images use semantic versioning you can filter by image tags that adhere to certain constraints:

fluxctl policy --workload=default:deployment/helloworld --tag-all='semver:~1'

or only release images that have a stable semantic version tag (X.Y.Z):

fluxctl policy --workload=default:deployment/helloworld --tag-all='semver:*'

Using a semver filter will also affect how Flux sorts images, so that the higher versions will be considered newer.

Regexp

If your images have complex tags you can filter by regular expression:

fluxctl policy --workload=default:deployment/helloworld --tag-all='regexp:^([a-zA-Z]+)$'

Instead of regexp it is also possible to use its alias regex. Please bear in mind that if you want to match the whole tag, you must bookend your pattern with ^ and $.

Controlling image timestamps with labels

Some image registries do not expose a reliable creation timestamp for image tags, which could pose a problem for the automated roll-out of images.

To overcome this problem you can define one of the supported labels in your Dockerfile. Flux will prioritize labels over the timestamp it retrieves from the registry.

Supported label formats

Actions triggered through fluxctl

fluxctl provides the following flags for the message and author customization:

  -m, --message string      attach a message to the update
      --user    string      override the user reported as initiating the update

Commit customization

1. Commit message

   fluxctl --message="Message providing more context for the action" .....

2. Committer

    Committer information can be overriden with the appropriate fluxd flags:

    --git-user
    --git-email

    See [site/daemon.md] for more information.

3. Commit author

    The default for the author is the committer information, which can be overriden,
    in the following manner:

    a) Default override uses user's git configuration, ie user.name
       and user.email (.gitconfig) to set the commit author.
       If the user has neither user.name nor for
       user.email set up, the committer information will be used. If only one
       is set up, that will be used.

    b) This can be further overriden by the use of the fluxctl --user flag.

    Examples

    a) fluxctl --user="Jane Doe <[email protected]>" ......
        This will always succeed as git expects a new author in the format
        "some_string <some_other_string>".

    b) fluxctl --user="Jane Doe" .......
        This form will succeed if there is already a repo commit, done by
        Jane Doe.

    c) fluxctl --user="[email protected]" .......
        This form will succeed if there is already a repo commit, done by
        [email protected].

Errors due to author customization

In case of no prior commit by the specified author, an error will be reported for b) and c):

git commit: fatal: --author 'unknown' is not 'Name <email>' and matches
no existing author

Using Annotations

Automation and image tag filtering can also be managed using annotations (fluxctl is using the same mechanism).

Automation can be enabled with flux.weave.works/automated: "true". Image filtering annotations take the form flux.weave.works/tag.container-name: filter-type:filter-value. Values of filter-type can be glob, semver, and regexp. Filter values use the same syntax as when the filter is configured using fluxctl.

Here's a simple but complete deployment file with annotations:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: podinfo
  namespace: demo
  labels:
    app: podinfo
  annotations:
    flux.weave.works/automated: "true"
    flux.weave.works/tag.podinfod: semver:~1.3
spec:
  selector:
    matchLabels:
      app: podinfo
  template:
    metadata:
      labels:
        app: podinfo
    spec:
      containers:
      - name: podinfod
        image: stefanprodan/podinfo:1.3.2
        ports:
        - containerPort: 9898
          name: http
        command:
        - ./podinfo
        - --port=9898

Things to notice:

  1. The annotations are made in metadata.annotations, not in spec.template.metadata.
  2. The flux.weave.works/tag.... references the container name podinfod, this will change based on your container name. If you have multiple containers you would have multiple lines like that.
  3. The value for the flux.weave.works/tag.... annotation should includes the filter pattern type, in this case semver.

Annotations can also be used to tell Flux to temporarily ignore certain manifests using flux.weave.works/ignore: "true". Read more about this in the FAQ.