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https://github.com/asobti/kube-monkey

An implementation of Netflix's Chaos Monkey for Kubernetes clusters
https://github.com/asobti/kube-monkey

chaos-monkey go kubernetes netflix-chaos-monkey

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An implementation of Netflix's Chaos Monkey for Kubernetes clusters

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kube-monkey is an implementation of [Netflix's Chaos Monkey](https://github.com/Netflix/chaosmonkey) for [Kubernetes](http://kubernetes.io/) clusters. It randomly deletes Kubernetes (k8s) pods in the cluster encouraging and validating the development of failure-resilient services.



Join us at [#kube-monkey](https://kubernetes.slack.com/messages/kube-monkey) on Kubernetes Slack.



---



kube-monkey runs at a pre-configured hour (`run_hour`, defaults to 8 am) on weekdays, and builds a schedule of deployments that will face a random

Pod death sometime during the same day. The time-range during the day when the random pod Death might occur is configurable and defaults to 10 am to 4 pm.



kube-monkey can be configured with a list of namespaces

* to blacklist (any deployments within a blacklisted namespace will not be touched)



To disable the blacklist provide `[""]` in the `blacklisted_namespaces` config.param.



## Opting-In to Chaos



kube-monkey works on an opt-in model and will only schedule terminations for Kubernetes (k8s) apps that have explicitly agreed to have their pods terminated by kube-monkey.



Opt-in is done by setting the following labels on a k8s app:



**`kube-monkey/enabled`**: Set to **`"enabled"`** to opt-in to kube-monkey  

**`kube-monkey/mtbf`**: Mean time between failure (in days). For example, if set to **`"3"`**, the k8s app can expect to have a Pod

killed approximately every third weekday.  

**`kube-monkey/identifier`**: A unique identifier for the k8s apps. This is used to identify the pods

that belong to a k8s app as Pods inherit labels from their k8s app. So, if kube-monkey detects that app `foo` has enrolled to be a victim, kube-monkey will look for all pods that have the label `kube-monkey/identifier: foo` to determine which pods are candidates for killing. The recommendation is to set this value to be the same as the app's name.  

**`kube-monkey/kill-mode`**: Default behavior is for kube-monkey to kill only ONE pod of your app. You can override this behavior by setting the value to:

* `kill-all` if you want kube-monkey to kill **ALL** of your pods regardless of status (including not ready and not running pods). Does not require `kill-value`. **Use this label carefully.**

* `fixed` if you want to kill a specific number of running pods with `kill-value`. If you overspecify, it will kill **all** running pods and issue a warning.

* `random-max-percent` to specify a *maximum* `%` with `kill-value` that can be killed. At the scheduled time, a uniform *random specified* `%` of the running pods will be terminated.

* `fixed-percent` to specify a *fixed* `%` with `kill-value` that can be killed. At the scheduled time, a specified *fixed* `%` of the running pods will be terminated.



**`kube-monkey/kill-value`**: Specify value for kill-mode

* if `fixed`, provide an integer of pods to kill

* if `random-max-percent`, provide a number from `0`-`100` to specify the max `%` of pods kube-monkey can kill

* if `fixed-percent`, provide a number from `0`-`100` to specify the `%` of pods to kill



#### Example of opted-in Deployment killing one pod per purge



```yaml

---

apiVersion: apps/v1

kind: Deployment

metadata:

  name: monkey-victim

  namespace: app-namespace

spec:

  template:

    metadata:

      labels:

        kube-monkey/enabled: enabled

        kube-monkey/identifier: monkey-victim

        kube-monkey/mtbf: '2'

        kube-monkey/kill-mode: "fixed"

        kube-monkey/kill-value: '1'

[... omitted ...]

```



For newer versions of kubernetes you may need to add the labels to the k8s app metadata as well.



```yaml

---

apiVersion: apps/v1

kind: Deployment

metadata:

  name: monkey-victim

  namespace: app-namespace

  labels:

    kube-monkey/enabled: enabled

    kube-monkey/identifier: monkey-victim

    kube-monkey/mtbf: '2'

    kube-monkey/kill-mode: "fixed"

    kube-monkey/kill-value: '1'

spec:

  template:

    metadata:

      labels:

        kube-monkey/enabled: enabled

        kube-monkey/identifier: monkey-victim

[... omitted ...]

```



### Overriding the apiserver

#### Use cases:

* Since client-go does not support [cluster dns](https://github.com/kubernetes/client-go/blob/master/rest/config.go#L331) explicitly with a `// TODO: switch to using cluster DNS.` note in the code, you may need to override the apiserver.

* If you are running an unauthenticated system, you may need to force the http apiserver endpoint.



#### To override the apiserver specify in the config.toml file

```toml

[kubernetes]

host="https://your-apiserver-url.com:apiport"

```



## How kube-monkey works



#### Scheduling time

Scheduling happens once a day on Weekdays - this is when a schedule for terminations for the current day is generated. During scheduling, kube-monkey will:  

1. Generate a list of eligible k8s apps (k8s apps that have opted-in and are not blacklisted, if specified, and are whitelisted, if specified)

2. For each eligible k8s app, flip a biased coin (bias determined by `kube-monkey/mtbf`) to determine if a pod for that k8s app should be killed today

3. For each victim, calculate a random time when a pod will be killed



#### Termination time

This is the randomly generated time during the day when a victim k8s app will have a pod killed.

At termination time, kube-monkey will:

1. Check if the k8s app is still eligible (has not opted-out or been blacklisted or removed from the whitelist since scheduling)

2. Check if the k8s app has updated kill-mode and kill-value

3. Depending on kill-mode and kill-value, execute pods



## Docker Images



Docker images for kube-monkey can be found at [DockerHub](https://hub.docker.com/r/ayushsobti/kube-monkey/tags/)



## Building



Clone the repository and build the container.



```bash

go get github.com/asobti/kube-monkey

cd $GOPATH/src/github.com/asobti/kube-monkey

make build

make container

```



## Configuring

kube-monkey is configured by environment variables or a toml file placed at `/etc/kube-monkey/config.toml` and expects the configmap to exist before the kube-monkey deployment.



Configuration keys and descriptions can be found in [`config/param/param.go`](https://github.com/asobti/kube-monkey/blob/master/internal/pkg/config/param/param.go)



#### Example config.toml file

```toml

[kubemonkey]

dry_run = true                           # Terminations are only logged

run_hour = 8                             # Run scheduling at 8am on weekdays

start_hour = 10                          # Don't schedule any pod deaths before 10am

end_hour = 16                            # Don't schedule any pod deaths after 4pm

blacklisted_namespaces = ["kube-system"] # Critical apps live here

time_zone = "America/New_York"           # Set tzdata timezone example. Note the field is time_zone not timezone

```



#### Example environment variables

```

KUBEMONKEY_DRY_RUN=true

KUBEMONKEY_RUN_HOUR=8

KUBEMONKEY_START_HOUR=10

KUBEMONKEY_END_HOUR=16

KUBEMONKEY_BLACKLISTED_NAMESPACES=kube-system

KUBEMONKEY_TIME_ZONE=America/New_York

```

#### Example Config to test kube-monkey works by enabling debug mode



Note: this will keep attacking pods every 60s regardless of what you configured for the `startHour` and `endHour`.



```toml

[debug]

enabled= true

schedule_immediate_kill= true

```



## Notifications



Kube-monkey supports notifications and can notify an endpoint of your choice after an attack.

It can be a Slack webhook or a custom API.



#### Example Config for posting attack notifications to an HTTP endpoint

```toml

[notifications]

  enabled = true

  reportSchedule = true

  [notifications.attacks]

    endpoint = "http://url1"

    message = "message1"

    headers = ["header1Key:header1Value","header2Key:header2/Value"]

```



#### Placeholders



The message supports the following placeholders:

* `{$name}`: victim's name

* `{$kind}`: victim's kind

* `{$namespace}`: victim's namespace

* `{$timestamp}`: attack's time from Unix epoch in milliseconds

* `{$time}`: attack's time

* `{$date}`: attack's date

* `{$error}`: result's error, if any

* `{$kubemonkeyid}`: kube-monkey id (set using KUBE_MONKEY_ID env variable otherwise empty)



```

  message: '{

            "what": "Kube-monkey(${kubemonkeyid}) attack of {$name} in {$namespace}",

            "who": "{$name}",

            "when": {$timestamp}

           }'

```



The header supports a special placeholder to retrieve the value of an environment variable.

This is useful when calling an API that has a protected endpoint.

A typical scenario will be to pass an API token to the Kube-monkey container, this token is stored in a Kubernetes Secret and you want to pass it via an environment variable.



```

headers = ["api-key:{$env:API_TOKEN}", "Content-Type:application/json"]

```



`{$env:API_TOKEN}` will be replaced by the environment variable `API_TOKEN` value.



Note if the environment variable does not exist, the notification call will NOT be cancelled. The value will resolve to an empty string, and a warning will show up in the logs. 



## Deploying



**Manually**

1. First, deploy the expected `kube-monkey-config-map` configmap in the namespace you intend to run kube-monkey in (for example, the `kube-system` namespace). Make sure to define the keyname as `config.toml`



> For example `kubectl create configmap km-config --from-file=config.toml=km-config.toml` or `kubectl apply -f km-config.yaml`



2. Run kube-monkey as a k8s app within the Kubernetes cluster, in a namespace that has permissions to kill Pods in other namespaces (eg. `kube-system`).



See dir [`examples/`](https://github.com/asobti/kube-monkey/tree/master/examples) for example Kubernetes yaml files.



3. You should be able to see debug logs by `kubectl logs -f deployment.apps/kube-monkey --namespace=kube-system`  here the `deployment.apps/kube-monkey` is the k8s deployment for kube-monkey.



**Helm Chart**  



See [How to install kube-monkey with Helm](helm/kubemonkey/README.md).



## Logging



kube-monkey uses [glog](github.com/golang/glog) and supports all command-line features for glog. To specify a custom v level or a custom log directory on the pod, see  `args: ["-v=5", "-log_dir=/path/to/custom/log"]` in the [example deployment file](https://github.com/asobti/kube-monkey/tree/master/examples/deployment.yaml)



> **Standardized glog levels `grep -r V\([0-9]\) *`**

>

> L0: None

>

> L1: Highest Level current status info and Errors with Terminations

>

> L2: Successful terminations

>

> L3: More detailed schedule status info

>

> L4: Debugging verbose schedule and config info

>

> L5: Auto-resolved inconsequential issues



More resources: See the [k8s logging page](https://kubernetes.io/docs/concepts/cluster-administration/logging/) suggesting [community conventions for logging severity](https://github.com/kubernetes/community/blob/master/contributors/devel/logging.md)



## Instructions on how to get this working on OpenShift 3.x



```

git clone https://github.com/asobti/kube-monkey.git

cd examples

oc login http://someserver/ -u system:admin

oc project kube-system

oc create -f configmap.yaml

oc -n kube-system adm policy add-role-to-user -z deployer system:deployer

oc -n kube-system adm policy add-role-to-user -z builder system:image-builder

oc -n kube-system adm policy add-role-to-group system:image-puller system:serviceaccounts:kube-system

oc run kube-monkey --image=docker.io/ayushsobti/kube-monkey:v0.4.0 --command -- /kube-monkey -v=5 -log_dir=/var/log/kube-monkey

oc volume dc/kube-monkey --add --name=kubeconfigmap -m /etc/kube-monkey -t configmap --configmap-name=kube-monkey-config-map

```



### OpenShift 4.x



```

git clone https://github.com/asobti/kube-monkey.git

cd examples

oc login http://someserver/ -u system:admin

oc project kube-system

oc create -f configmap.yaml

oc -n kube-system adm policy add-cluster-role-to-user edit -z default --rolebinding-name kube-monkey-edit

oc run kube-monkey --image=docker.io/ayushsobti/kube-monkey:v0.3.0 --command -- /kube-monkey -v=5 -log_dir=/var/log/kube-monkey

oc set volume dc/kube-monkey --add --name=kubeconfigmap -m /etc/kube-monkey -t configmap --configmap-name=kube-monkey-config-map

```



## Ways to contribute



See [How to Contribute](CONTRIBUTING.md)



## License

This project is licensed under the Apache License v2.0 - see the [LICENSE](LICENSE) file for details.