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MustacheTemplate

Build Status GitHub

MustacheTemplate is the next step of complexity when working with Razee. With MustacheTemplate we can inject cluster specific environment variables into resources before applying them to a cluster. We even use this injection method as the mechanism for version control of our resources.

The basic operation of MustacheTemplate is to collect all values defined in .spec.envFrom and .spec.env, then use those values to process all yaml defined in the .spec.templates, and finally apply the processed yaml to the cluster.

Install

Razee Deploy Delta is the recommended way to install MustacheTemplate.

Optional: Advanced Controller Options

Warning: By default, Razeedeploy runs as cluster wide admin. Any user that has permission to create a razeedeploy resource (RemoteResource or MustacheTemplate) has the ability to escalate their privileges. To prevent privilege escalation, cluster owners should restrict which users are allowed to create razeedeploy resources. Alternatively, you can setup ImpersonationWebhook and then enable user impersonation to ensure razeedeploy only allows users to do operations that they have already been granted access to do.

Resource Definition

Sample

apiVersion: deploy.razee.io/v1alpha2
kind: MustacheTemplate
metadata:
  name: <mustache_template_name>
  namespace: <namespace>
spec:
  clusterAuth:
    impersonateUser: razeedeploy
  envFrom:
    - genericMapRef:
        apiVersion: deploy.razee.io/v1alpha2
        kind: FeatureFlagSetLD
        name: myLDProject
        namespace: default
  env:
    - name: app-label
      value: "deployment 1"
    - name: desired-replicas
      optional: true
      default: 3
      valueFrom:
        configMapKeyRef:
          name: nginx-config
          key: replicas
          type: number
    - name: json-config
      valueFrom:
        configMapKeyRef:
          name: nginx-config-globals
          key: my-app-config
          type: json
    - name: json-config
      overrideStrategy: merge
      valueFrom:
        configMapKeyRef:
          name: nginx-config-dev
          key: my-app-config-dev-overrides
          type: json
    - name: json-merge-selectors
      overrideStrategy: merge
      valueFrom:
        configMapKeyRef:
          matchLabels:
            app: json-rules-merge
          key: json-config
          type: json
  templates:
    - apiVersion: v1
      kind: ConfigMap
      metadata:
        name: test-config
      data:
        sample: "{{ desired-replicas }}"
  strTemplates:
    - |
      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: nginx-deployment
        labels:
          app: nginx
          deployment: {{ app-label }}
      spec:
        replicas: {{ desired-replicas }}
        selector:
          matchLabels:
            app: nginx
        template:
          metadata:
            labels:
              app: nginx
          spec:
            containers:
            - name: nginx
              image: nginx:1.7.9
              ports:
              - containerPort: 80

Spec

Path: .spec

Description: spec is required and must include at least one [envFrom , env] and at least one [templates, strTemplates].

Schema:

spec:
  type: object
  allOf:
    - anyOf:
        - required: [templates]
        - required: [strTemplates]
    - anyOf:
        - required: [envFrom]
        - required: [env]
  properties:
    clusterAuth:
      type: object
      ...
    templateEngine:
      type: string
      ...
    custom-tags:
      type: array
      ...
    envFrom:
      type: array
      ...
    env:
      type: array
      ...
    templates:
      type: array
      ...
    strTemplates:
      type: array
      ...

User Impersonation

Path: .spec.clusterAuth.impersonateUser

Description: Impersonates a user for the given resource. This includes all actions the controller must make related to the resource (fetching envs, getting resources, applying resources, etc.). ImpersonateUser only applies to the single RazeeDeploy resource that it has been added to.

Enable Feature: Enable User Impersonation

Warning: By default, Razeedeploy runs as cluster wide admin. Any user that has permission to create a razeedeploy resource (RemoteResource or MustacheTemplate) has the ability to escalate their privileges. To prevent privilege escalation, cluster owners should restrict which users are allowed to create razeedeploy resources. Alternatively, you can setup ImpersonationWebhook and then enable user impersonation to ensure razeedeploy only allows users to do operations that they have already been granted access to do.

Schema:

properties:
  clusterAuth:
    type: object
    properties:
      impersonateUser:
        type: string

Default: 'razeedeploy'

Templating Engine

Path: .spec.templateEngine

Description: Specifying which templating engine to use, the available options are mustache and handlebars

Schema:

properties:
  templateEngine:
    type: string
    pattern: "^mustache$|^handlebars$"

Default: 'mustache'

Custom Tags

Path: .spec.custom-tags

Description: Specifying custom tags will override the default mustache tags. This can be useful when you need to reserve {{ }} for some other processing.

Schema:

custom-tags:
  type: array
  maxItems: 2
  minItems: 2
  items:
    type: string
    maxLength: 3
    minLength: 2

Default: ['{{', '}}']

EnvFrom

Path: .spec.envFrom

Description: Allows you to pull in all values from a resource's .data section to be used in template processing. ie. ConfigMaps would use the configMapRef key and CRDs with a high level .data section can be pulled in by using the genericMapRef key. The keys pulled from the resource are what you would use to match values into your templates.

Note: values are loaded in from .spec.envFrom before .spec.env, and top down. Any values with the same key/name will be overwritten, last in wins.

Schema:

envFrom:
  type: array
  items:
    type: object
    oneOf:
      - required: [configMapRef]
      - required: [secretMapRef]
      - required: [genericMapRef]
    properties:
      optional:
        type: boolean
      configMapRef:
        type: object
        required: [name]
        properties:
          name:
            type: string
          namespace:
            type: string
      secretMapRef:
        type: object
        required: [name]
        properties:
          name:
            type: string
          namespace:
            type: string
      genericMapRef:
        type: object
        required: [apiVersion, kind, name]
        properties:
          apiVersion:
            type: string
          kind:
            type: string
          name:
            type: string
          namespace:
            type: string

EnvFrom Optional

Path: .spec.envFrom[].optional

Description: If fetching env/envFrom resource fails, MustacheTemplate will stop execution and report error to .status. You can allow execution to continue by marking a reference as optional.

Schema:

optional:
  type: boolean

Default: false

Env

Path: .spec.env

Description: Allows you to pull in a single value from a resource's .data section to be used in template processing. ie. ConfigMaps would use the configMapKeyRef key and CRDs with a high level .data section can be pulled from by using the genericKeyRef key. .spec.env.name is what you would use to match values into your templates. You can also specify a type that we will convert your fetched string into, before injecting into your template (one of [number, boolean, json, jsonString, base64]). Note: when no type is specified, the value will be treated as a normal string.

Note: values are loaded in from .spec.envFrom before .spec.env, and top down. Any values with the same key/name will be overwritten, last in wins. If you want to have json values merged, specify overrideStrategy: merge

Schema:

env:
  type: array
  items:
    type: object
    allOf:
      - required: [name]
      - # all array items should be oneOf ['value', 'valueFrom']
        oneOf:
          - required: [value]
            # if 'value', neither 'optional' nor 'default' may be used
            not:
              anyOf:
                - required: [default]
                - required: [optional]
          - required: [valueFrom]
            # if 'valueFrom', you must define oneOf:
            oneOf:
              - # neither 'optional' nor 'default' is used
                not:
                  anyOf:
                    - required: [default]
                    - required: [optional]
              - # 'optional' is used by itself
                required: [optional]
                not:
                  required: [default]
              - # 'optional' and 'default' are used together IFF optional == true
                required: [optional, default]
                properties:
                  optional:
                    enum: [true]
    properties:
      optional:
        type: boolean
      default:
        x-kubernetes-int-or-string: true
      name:
        type: string
      overrideStrategy:
        type: string
        pattern: "^merge$|^replace$"
      value:
        x-kubernetes-int-or-string: true
      valueFrom:
        type: object
        oneOf:
          - required: [configMapKeyRef]
          - required: [secretKeyRef]
          - required: [genericKeyRef]
        properties:
          configMapKeyRef:
            type: object
            oneOf:
              - required: [key, name]
              - required: [key, matchLabels]
            properties:
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]
              matchLabels:
                type: object
                additionalProperties: true
          secretKeyRef:
            type: object
            oneOf:
              - required: [key, name]
              - required: [key, matchLabels]
            properties:
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]
              matchLabels:
                type: object
                additionalProperties: true
          genericKeyRef:
            type: object
            oneOf:
              - required: [apiVersion, kind, name, key]
              - required: [apiVersion, kind, matchLabels, key]
            properties:
              apiVersion:
                type: string
              kind:
                type: string
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]
              matchLabels:
                type: object
                additionalProperties: true

Env Optional

Path: .spec.env[].optional

Description: If fetching env/envFrom resource fails, MustacheTemplate will stop execution and report error to .status. You can allow execution to continue by marking a reference as optional: true.

Schema:

optional:
  type: boolean

Default: false

Env Default

Path: .spec.env[].default

Description: If fetching env/envFrom resource fails, but .spec.env[].optional is true and .spec.env[].default is defined, the default value will be used.

Schema:

default:
  x-kubernetes-int-or-string: true

Env OverrideStrategy

Path: .spec.env[].overrideStrategy

Description: If you are loading envs as json, and you want to allow overrided values to merge instead of just replacing, specify overrideStrategy: merge.

Note: If either env defined is not a json object when merge is specified, the behavior will revert to replace instead of merge (ie. a json object is loaded first, then a jsonString is loaded second with overrideStrategy: merge specified. the jsonString will replace the first json object instead of trying to merge with it.)

Schema:

overrideStrategy:
  type: string
  pattern: "^merge$|^replace$"

Default: replace

Managed Resource Labels

Reconcile

.spec.templates.metadata.labels[deploy.razee.io/Reconcile]

  • DEFAULT: true
    • A razeedeploy resource (parent) will clean up a resources it applies (child) when either the child is no longer in the parent resource definition or the parent is deleted.
  • false
    • This behavior can be overridden when a child's resource definition has the label deploy.razee.io/Reconcile=false.

Resource Update Mode

.spec.templates.metadata.labels[deploy.razee.io/mode]

Razeedeploy resources default to merge patching children. This behavior can be overridden when a child's resource definition has the label deploy.razee.io/mode=<mode>

Mode options:

  • DEFAULT: Apply (MergePatch)
    • A simple merge, that will merge objects and replace arrays. Items previously defined, then removed from the definition, will be removed from the live resource.
    • "As defined in RFC7386, a Merge Patch is essentially a partial representation of the resource. The submitted JSON is "merged" with the current resource to create a new one, then the new one is saved. For more details on how to use Merge Patch, see the RFC." Reference
  • StrategicMergePatch
    • A more complicated merge, the kubernetes apiServer has defined keys to be able to intelligently merge arrays it knows about.
    • "Strategic Merge Patch is a custom implementation of Merge Patch. For a detailed explanation of how it works and why it needed to be introduced, see StrategicMergePatch." Reference
    • Kubectl Apply Semantics
  • AdditiveMergePatch
    • Similar to the default Apply (MergePatch), this is a simple merge, that will merge objects and replace arrays. The difference is that it will not remove fields from the live resource when they are removed from the definition. eg. This will only add/update fields, it wont remove fields.
    • If you are using this mode and find that you need to remove a field, you can do so manually, by setting the field in the yaml defintion to have a value of null. When the null value is merged with the live resource, it will effectively delete the field.
    • This mode is useful if you have very large resources and require that the last-applied-configuration annotation is not injected into the resource.
  • EnsureExists
    • Will ensure the resource is created and is replaced if deleted. Will not enforce a definition.

Debug Individual Resource

.spec.resources.metadata.labels[deploy.razee.io/debug]

Treats the live resource as EnsureExist. If any Kapitan component is enforcing the resource, and the label deploy.razee.io/debug: true exists on the live resource, it will treat the resource as ensure exist and not override any changes. This is useful for when you need to debug a live resource and don't want Kapitan overriding your changes. Note: this will only work when you add it to live resources. If you want to have the EnsureExist behavior, see Resource Update Mode.

  • ie: kubectl label mtp <your-mtp> deploy.razee.io/debug=true

Cluster Wide Controls

The optional razeedeploy-config ConfigMap can be used to customize the controller for cluster wide actions.

Because the ConfigMap is optional, if it is created the first time, you must restart controller pods, so the deployment can mount the ConfigMap as a volume.

Example:

apiVersion: v1
kind: ConfigMap
metadata:
  name: razeedeploy-config
  namespace: razeedeploy
data:
  lock-cluster: "false"
  enable-impersonation: "false"

Lock Cluster

Key: lock-cluster

Options:

  • DEFAULT: false
    • Allows the controller to continue normal operations on the cluster.
  • true
    • Prevents the controller from updating resources on the cluster.

Enable Cluster Wide User Impersonation

Key: enable-impersonation

Options:

  • DEFAULT: false
    • Prevents the controller from performing user impersonation in all namespaces. Continues to allow user impersonation in the razeedeploy namespace. To prevent privildge escalation, users should be restricted from creating razeedeploy resources.
  • true
    • Allows the controller to perform user impersonation in all namespaces. See important note below about steps that should be taken to properly configure this feature before enabling.

IMPORTANT: it is highly advised to set up ImpersonationWebhook before enabling cluster-wide impersonation. If ImpersonationWebhook is not installed before enabling impersonation, any user on the cluster that is allowed to create razeedeploy resources will be able to impersonate any other user. Once the ImpersonationWebhook controller is installed and all necessary config and authorizations in place, impersonation can be safely enabled in the razeedeploy-config configmap.

Local Testing with bin/renderlocal

bin/renderlocal can be used to see what the resources generated by a MustacheTemplate would look like.

bin/renderlocal arguments:

  • --mtp a path to the template you want to render.
  • --env a path to a file containing ConfigMaps, Secrets, or other resources used to render the template. Any number of --env files can be added; at least one is required.
  • --out if provided, the path to write the resulting rendered resources [OPTIONAL]

Example

bin/renderlocal --mtp test/example/hello-mtp.yaml --env test/example/hello-cm.yaml

{..."failed to get env: {\"name\":\"greeting\",... # expected warning
kind: ConfigMap
apiVersion: v1
metadata:
  name: result
  namespace: default
data:
  result: hello, Razee!
bin/renderlocal --mtp test/example/hello-mtp.yaml \
--env test/example/hello-cm.yaml --env test/example/alternate-greeting-cm.yaml

kind: ConfigMap
apiVersion: v1
metadata:
  name: result
  namespace: default
data:
  result: howdy, Razee!
bin/renderlocal --mtp test/example/hello-mtp.yaml \
--env test/example/hello-cm.yaml --env test/example/alternate-greeting-cm.yaml \
--out /tmp/output.yaml \
&& cat /tmp/output.yaml

kind: ConfigMap
apiVersion: v1
metadata:
  name: result
  namespace: default
data:
  result: howdy, Razee!