# Kubernetes Input Plugin

This plugin gathers metrics about running pods and containers of a
[Kubernetes][kubernetes] instance via the Kubelet API.

> [!NOTE]
> This plugin has to run as part of a `daemonset` within a Kubernetes
> installation.
> Telegraf must run on every node within the cluster.

You should configure this plugin to talk to its locally running kubelet.

> [!CRITICAL]
> This plugin produces high cardinality data, which when not controlled for will
> cause high load on your database. Please make sure to [filter][filtering] the
> produced metrics or configure your database to avoid cardinality issues!

⭐ Telegraf v1.1.0
🏷️ containers
💻 all

[kubernetes]: https://kubernetes.io/
[filtering]: /docs/CONFIGURATION.md#metric-filtering

## Global configuration options <!-- @/docs/includes/plugin_config.md -->

Plugins support additional global and plugin configuration settings for tasks
such as modifying metrics, tags, and fields, creating aliases, and configuring
plugin ordering. See [CONFIGURATION.md][CONFIGURATION.md] for more details.

[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins

## Configuration

```toml @sample.conf
# Read metrics from the kubernetes kubelet api
[[inputs.kubernetes]]
  ## URL for the kubelet, if empty read metrics from all nodes in the cluster
  url = "http://127.0.0.1:10255"

  ## Use bearer token for authorization.
  # bearer_token = "/var/run/secrets/kubernetes.io/serviceaccount/token"

  ## Kubernetes Node Metric Name
  ## The default Kubernetes node metric name (kubernetes_node) is the same
  ## for the kubernetes and kube_inventory plugins. To avoid conflicts, set this
  ## option to a different value.
  # node_metric_name = "kubernetes_node"

  ## Pod labels to be added as tags.  An empty array for both include and
  ## exclude will include all labels.
  # label_include = []
  # label_exclude = ["*"]

  ## Set response_timeout (default 5 seconds)
  # response_timeout = "5s"

  ## Optional TLS Config
  # tls_ca = /path/to/cafile
  # tls_cert = /path/to/certfile
  # tls_key = /path/to/keyfile
  ## Use TLS but skip chain & host verification
  # insecure_skip_verify = false
```

### Host IP

To find the ip address of the host you are running on you can issue a command
like the following:

```sh
curl -s $API_URL/api/v1/namespaces/$POD_NAMESPACE/pods/$HOSTNAME \
  --header "Authorization: Bearer $TOKEN" \
  --insecure | jq -r '.status.hostIP'
```

This example uses the downward API to pass in the `$POD_NAMESPACE` and
`$HOSTNAME` is the hostname of the pod which is set by the kubernetes API.
See the [Kubernetes documentation][Kubernetes_docs] for a full example of
generating a bearer token to explore the Kubernetes API.

[Kubernetes_docs]: https://kubernetes.io/docs/tasks/administer-cluster/access-cluster-api/#without-kubectl-proxy

### Daemon-set

For recommendations on running Telegraf as a daemon-set see the
[Monitoring Kubernetes Architecture blog post][k8s_telegraf_blog] or check the
following Helm charts:

- [Telegraf][helm_telegraf]
- [InfluxDB][helm_influxdb]
- [Chronograf][helm_chronograf]
- [Kapacitor][helm_kapacitor]

### RBAC Permissions

When `url` is left empty (cluster mode), the plugin uses the Kubernetes API to
discover all nodes in the cluster, then connects to each node's Kubelet
on port 10250. This requires a `ClusterRole` with the following permissions:

- **apiGroups**: `""` (core)
- **resources**: `"nodes"`
- **verbs**: `"list"`, `"get"`

Refer to the [Kubernetes RBAC documentation][rbac] for creating the appropriate
ClusterRole and ClusterRoleBinding.

When `url` is explicitly set (e.g., `url = "http://127.0.0.1:10255"`), the plugin
only talks to the local Kubelet API and does **not** use the Kubernetes API server,
so no Kubernetes RBAC permissions are required.

[k8s_telegraf_blog]: https://www.influxdata.com/blog/monitoring-kubernetes-architecture/
[helm_telegraf]: https://github.com/helm/charts/tree/master/stable/telegraf
[helm_influxdb]: https://github.com/helm/charts/tree/master/stable/influxdb
[helm_chronograf]: https://github.com/helm/charts/tree/master/stable/chronograf
[helm_kapacitor]: https://github.com/helm/charts/tree/master/stable/kapacitor
[rbac]: https://kubernetes.io/docs/reference/access-authn-authz/rbac/

## Metrics

- kubernetes_node
  - tags:
    - node_name
  - fields:
    - cpu_usage_nanocores
    - cpu_usage_core_nanoseconds
    - memory_available_bytes
    - memory_usage_bytes
    - memory_working_set_bytes
    - memory_rss_bytes
    - memory_page_faults
    - memory_major_page_faults
    - network_rx_bytes
    - network_rx_errors
    - network_tx_bytes
    - network_tx_errors
    - fs_available_bytes
    - fs_capacity_bytes
    - fs_used_bytes
    - runtime_image_fs_available_bytes
    - runtime_image_fs_capacity_bytes
    - runtime_image_fs_used_bytes

- kubernetes_pod_container
  - tags:
    - container_name
    - namespace
    - node_name
    - pod_name
  - fields:
    - cpu_usage_nanocores
    - cpu_usage_core_nanoseconds
    - memory_usage_bytes
    - memory_working_set_bytes
    - memory_rss_bytes
    - memory_page_faults
    - memory_major_page_faults
    - rootfs_available_bytes
    - rootfs_capacity_bytes
    - rootfs_used_bytes
    - logsfs_available_bytes
    - logsfs_capacity_bytes
    - logsfs_used_bytes

- kubernetes_pod_volume
  - tags:
    - volume_name
    - namespace
    - node_name
    - pod_name
  - fields:
    - available_bytes
    - capacity_bytes
    - used_bytes

- kubernetes_pod_network
  - tags:
    - namespace
    - node_name
    - pod_name
  - fields:
    - rx_bytes
    - rx_errors
    - tx_bytes
    - tx_errors

## Example Output

```text
kubernetes_node
kubernetes_pod_container,container_name=deis-controller,namespace=deis,node_name=ip-10-0-0-0.ec2.internal,pod_name=deis-controller-3058870187-xazsr cpu_usage_core_nanoseconds=2432835i,cpu_usage_nanocores=0i,logsfs_available_bytes=121128271872i,logsfs_capacity_bytes=153567944704i,logsfs_used_bytes=20787200i,memory_major_page_faults=0i,memory_page_faults=175i,memory_rss_bytes=0i,memory_usage_bytes=0i,memory_working_set_bytes=0i,rootfs_available_bytes=121128271872i,rootfs_capacity_bytes=153567944704i,rootfs_used_bytes=1110016i 1476477530000000000
kubernetes_pod_network,namespace=deis,node_name=ip-10-0-0-0.ec2.internal,pod_name=deis-controller-3058870187-xazsr rx_bytes=120671099i,rx_errors=0i,tx_bytes=102451983i,tx_errors=0i 1476477530000000000
kubernetes_pod_volume,volume_name=default-token-f7wts,namespace=default,node_name=ip-172-17-0-1.internal,pod_name=storage-7 available_bytes=8415240192i,capacity_bytes=8415252480i,used_bytes=12288i 1546910783000000000
kubernetes_system_container
```
