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Using Carvel kapp

kapp is a CLI tool backed by VMware which can deploy groups of Kubernetes objects as independent applications in a safe and predictable manner.

The example below demonstrates how to use kapp to deploy a TriggerMesh Bridge and manage its lifecycle.

Deployment

The kapp tool allows deploying a Bridge List-manifest directly using the kapp deploy command. In a Bash-compatible shell, this can be achieved in a single step using a process substitution:

$ kapp deploy -a my-bridge --yes -f <(til generate my-bridge.brg.hcl)
Target cluster 'https://my-cluster.example.com' (nodes: node-1, 2+)

Changes

Namespace  Name        Kind       Conds.  Age  Op      Op st.  Wait to    Rs  Ri
default    some-name   SomeKind   -       -    create  -       reconcile  -   -
^          other-name  OtherKind  -       -    create  -       reconcile  -   -
[...]

Op:      6 create, 0 delete, 0 update, 0 noop
Wait to: 6 reconcile, 0 delete, 0 noop

Continue? [yN]: y

2:51:35PM: ---- applying 6 changes [0/6 done] ----
2:51:37PM: create somekind/some-name (example/v1) namespace: default
2:51:37PM: create otherkind/other-name (example/v1) namespace: default
[...]
2:51:39PM: ---- waiting on 6 changes [0/6 done] ----
2:51:40PM: ok: reconcile somekind/some-name (example/v1) namespace: default
2:51:40PM: ok: reconcile otherkind/other-name (example/v1) namespace: default
[...]
2:51:40PM: ---- applying complete [6/6 done] ----
2:51:40PM: ---- waiting complete [6/6 done] ----

Succeeded

The command shown in the previous example is equivalent to saving the generated List-manifest to a file prior to deploying it:

$ til generate my-bridge.brg.hcl > my-bridge-manifest.json

$ kapp deploy -a my-bridge -f my-bridge-manifest.json

Alternatively, a List-manifest can be piped to the kapp deploy command by using the - notation as the file name, which corresponds to the standard input. Please note that piping data to kapp requires the usage of the --yes flag, which bypasses the interactive user approval:

$ til generate my-bridge.brg.hcl | kapp deploy -a my-bridge --yes -f -

The deployed Bridge should appear in the list of kapp applications:

$ kapp list
Target cluster 'https://my-cluster.example.com' (nodes: node-1, 2+)

Apps in namespace 'default'

Name       Namespaces  Lcs   Lca
my-bridge  default     true  6m

Lcs: Last Change Successful
Lca: Last Change Age

1 apps

Succeeded

Updates

Any future modification to the Bridge description can be applied to the deployed application using the same deploy command and parameters used during the initial deployment. All pending changes are printed in the terminal and must be approved by the user, unless the --yes flag is set:

$ kapp deploy -a my-bridge -f my-bridge-manifest.json
Target cluster 'https://my-cluster.example.com' (nodes: node-1, 2+)

Changes

Namespace  Name        Kind       Conds.  Age  Op      Op st.  Wait to    Rs  Ri
default    some-name   SomeKind   5/5 t   14m  update  -       reconcile  ok  -
^          other-name  OtherKind  5/5 t   14m  delete  -       delete     ok  -

Op:      0 create, 1 delete, 1 update, 0 noop
Wait to: 1 reconcile, 1 delete, 0 noop

Continue? [yN]: y

3:05:57PM: ---- applying 2 changes [0/2 done] ----
3:05:58PM: update somekind/some-name (example/v1) namespace: default
3:05:58PM: delete otherkind/other-name (example/v1) namespace: default
3:05:59PM: ---- waiting on 2 changes [0/2 done] ----
3:06:00PM: ok: reconcile somekind/some-name (example/v1) namespace: default
3:06:01PM: ok: delete otherkind/other-name (example/v1) namespace: default
3:06:01PM: ---- applying complete [2/2 done] ----
3:06:01PM: ---- waiting complete [2/2 done] ----

Succeeded

Termination

To undo the deployment of an entire Bridge, simply uninstall its kapp application:

$ kapp delete -a my-bridge
Target cluster 'https://my-cluster.example.com' (nodes: node-1, 2+)

Changes

Namespace  Name        Kind       Conds.  Age  Op      Op st.  Wait to    Rs  Ri
default    some-name   SomeKind   5/5 t   20m  delete  -       reconcile  ok  -
[...]

Op:      0 create, 5 delete, 0 update, 0 noop
Wait to: 0 reconcile, 5 delete, 0 noop

Continue? [yN]: y

3:12:02PM: ---- applying 5 changes [0/5 done] ----
3:12:04PM: delete somekind/some-name (example/v1) namespace: default
[...]
3:12:04PM: ---- waiting on 5 changes [0/5 done] ----
3:12:04PM: ok: delete somekind/some-name (example/v1) namespace: default
[...]
3:12:04PM: ---- applying complete [5/5 done] ----
3:12:04PM: ---- waiting complete [5/5 done] ----

Succeeded