# VMs monitoring 
SkyWalking leverages Prometheus node-exporter for collecting metrics data from the VMs, and leverages OpenTelemetry Collector to transfer the metrics to
[OpenTelemetry receiver](backend-receivers.md#opentelemetry-receiver) and into the [Meter System](./../../concepts-and-designs/meter.md).  
We defined the VM entity as a `Service` in OAP, use `vm::` as a prefix to identify.  

## Data flow
1. Prometheus node-exporter collects metrics data from the VMs.
2. OpenTelemetry Collector fetches metrics from node-exporter via Prometheus Receiver and pushes metrics to SkyWalking OAP Server via the OpenCensus GRPC Exporter.
3. The SkyWalking OAP Server parses the expression with [MAL](../../concepts-and-designs/mal.md) to filter/calculate/aggregate and store the results. 

## Setup 
1. Setup [Prometheus node-exporter](https://prometheus.io/docs/guides/node-exporter/).
2. Setup [OpenTelemetry Collector ](https://opentelemetry.io/docs/collector/). This is an example for OpenTelemetry Collector configuration [otel-collector-config.yaml](../../../../test/e2e/e2e-test/docker/promOtelVM/otel-collector-config.yaml).
3. Config SkyWalking [OpenTelemetry receiver](backend-receivers.md#opentelemetry-receiver).
   
## Supported Metrics

| Monitoring Panel | Unit | Metric Name | Description | Data Source |
|-----|-----|-----|-----|-----|
| CPU Usage | % | cpu_total_percentage | The CPU cores total used percentage, if there are 2 cores the max usage is 200% | Prometheus node-exporter |
| Memory RAM Usage | MB | meter_vm_memory_used | The RAM total usage | Prometheus node-exporter |
| Memory Swap Usage | % | meter_vm_memory_swap_percentage | The swap memory used percentage | Prometheus node-exporter |
| CPU Average Used | % | meter_vm_cpu_average_used | The CPU cores used percentage in each mode | Prometheus node-exporter |
| CPU Load |  | meter_vm_cpu_load1<br />meter_vm_cpu_load5<br />meter_vm_cpu_load15 | The CPU 1m / 5m / 15m average load | Prometheus node-exporter |
| Memory RAM | MB | meter_vm_memory_total<br />meter_vm_memory_available<br />meter_vm_memory_used | The RAM statistics, include Total / Available / Used | Prometheus node-exporter |
| Memory Swap | MB | meter_vm_memory_swap_free<br />meter_vm_memory_swap_total | The Swap Memory statistics, include Free / Total | Prometheus node-exporter |
| File System Mountpoint Usage | % | meter_vm_filesystem_percentage | The File System used percentage in each mount point | Prometheus node-exporter |
| Disk R/W | KB/s | meter_vm_disk_read,meter_vm_disk_written | The Disk read and written | Prometheus node-exporter |
| Network Bandwidth Usage | KB/s | meter_vm_network_receive<br />meter_vm_network_transmit | The Network receive and transmit | Prometheus node-exporter |
| Network Status |  | meter_vm_tcp_curr_estab<br />meter_vm_tcp_tw<br />meter_vm_tcp_alloc<br />meter_vm_sockets_used<br />meter_vm_udp_inuse | The number of the TCP establish / TCP time wait / TCP allocated / Sockets inuse / UDP inuse | Prometheus node-exporter |
| Filefd Allocated |  | meter_vm_filefd_allocated | The number of the File Descriptor allocated | Prometheus node-exporter |

## Customizing 
You can customize your own metrics/expression/dashboard panel.   
The metrics definition and expression rules are in `/config/otel-oc-rules/vm.yaml`.  
The dashboard panel confirmations are in `/config/ui-initialized-templates/vm.yml`.

## Blog
A related blog can see: [SkyWalking 8.4 provides infrastructure monitoring](https://skywalking.apache.org/blog/2021-02-07-infrastructure-monitoring/)

# K8s monitoring 
SkyWalking leverages K8s kube-state-metrics and cAdvisor for collecting metrics data from the K8s, and leverages OpenTelemetry Collector to transfer the metrics to
[OpenTelemetry receiver](backend-receivers.md#opentelemetry-receiver) and into the [Meter System](./../../concepts-and-designs/meter.md). This feature requires authorizing the OAP Server to access K8s's `API Server`.  
We defined the k8s-cluster as a `Service` in OAP, use `k8s-cluster::` as a prefix to identify.  
Defined the k8s-node as an `Instance` in OAP, the name is k8s `node name`.  
Defined the k8s-service as an `Endpoint` in OAP, the name is `$serviceName.$namespace`.  

## Data flow
1. K8s kube-state-metrics and cAdvisor collects metrics data from the K8s.
2. OpenTelemetry Collector fetches metrics from kube-state-metrics and cAdvisor via Prometheus Receiver and pushes metrics to SkyWalking OAP Server via the OpenCensus GRPC Exporter.
3. The SkyWalking OAP Server access to K8s's `API Server` gets meta info and parses the expression with [MAL](../../concepts-and-designs/mal.md) to filter/calculate/aggregate and store the results. 

## Setup 
1. Setup [kube-state-metric](https://github.com/kubernetes/kube-state-metrics#kubernetes-deployment).
2. cAdvisor is integrated into `kubelet` by default.
3. Setup [OpenTelemetry Collector ](https://opentelemetry.io/docs/collector/getting-started/#kubernetes). Prometheus Receiver in OpenTelemetry Collector for K8s can reference [here](https://github.com/prometheus/prometheus/blob/main/documentation/examples/prometheus-kubernetes.yml). For a quick start, we provided a full example for OpenTelemetry Collector configuration [otel-collector-config.yaml](otel-collector-config.yaml).
4. Config SkyWalking [OpenTelemetry receiver](backend-receivers.md#opentelemetry-receiver).

## Supported Metrics
From the different point of view to monitor the K8s, there are 3 kinds of metrics: [Cluster](#cluster) / [Node](#node) / [Service](#service) 

### CLuster 
These metrics are related to the selected cluster(`Current Service in the dashboard`).

| Monitoring Panel | Unit | Metric Name | Description | Data Source |
|-----|-----|-----|-----|-----|
| Node Total |  | k8s_cluster_node_total | The number of the nodes | K8s kube-state-metrics|
| Namespace Total |  | k8s_cluster_namespace_total | The number of the namespaces | K8s kube-state-metrics|
| Deployment Total |  | k8s_cluster_deployment_total | The number of the deployments | K8s kube-state-metrics|
| Service Total |  | k8s_cluster_service_total | The number of the services | K8s kube-state-metrics|
| Pod Total |  | k8s_cluster_pod_total | The number of the pods | K8s kube-state-metrics|
| Container Total |  | k8s_cluster_container_total | The number of the containers | K8s kube-state-metrics|
| CPU Resources | m | k8s_cluster_cpu_cores<br />k8s_cluster_cpu_cores_requests<br />k8s_cluster_cpu_cores_limits<br />k8s_cluster_cpu_cores_allocatable | The capacity and the Requests / Limits / Allocatable of the CPU | K8s kube-state-metrics|
| Memory Resources | GB | k8s_cluster_memory_total<br />k8s_cluster_memory_requests<br />k8s_cluster_memory_limits<br />k8s_cluster_memory_allocatable | The capacity and the Requests / Limits / Allocatable of the memory | K8s kube-state-metrics|
| Storage Resources | GB | k8s_cluster_storage_total<br />k8s_cluster_storage_allocatable | The capacity and allocatable of the storage | K8s kube-state-metrics|
| Node Status |  | k8s_cluster_node_status | The current status of the nodes | K8s kube-state-metrics|
| Deployment Status |  | k8s_cluster_deployment_status | The current status of the deployment | K8s kube-state-metrics|
| Deployment Spec Replicas |  | k8s_cluster_deployment_spec_replicas | The number of desired pods for a deployment | K8s kube-state-metrics|
| Service Status |  | k8s_cluster_service_pod_status | The services current status, depending on the related pods' status | K8s kube-state-metrics|
| Pod Status Not Running |  | k8s_cluster_pod_status_not_running | The pods which the current phase is not running | K8s kube-state-metrics|
| Pod Status Waiting |  | k8s_cluster_pod_status_waiting | The pods and containers which currently in the waiting status, and show the reason | K8s kube-state-metrics|
| Pod Status Terminated |  | k8s_cluster_container_status_terminated | The pods and containers which currently in the terminated status, and show the reason | K8s kube-state-metrics|

### Node
These metrics are related to the selected node (`Current Instance in the dashboard`).

| Monitoring Panel | Unit | Metric Name | Description | Data Source |
|-----|-----|-----|-----|-----|
| Pod Total |  | k8s_node_pod_total | The number of the pods which in this node | K8s kube-state-metrics |
| Node Status |  | k8s_node_node_status | The current status of this node | K8s kube-state-metrics |
| CPU Resources | m | k8s_node_cpu_cores<br />k8s_node_cpu_cores_allocatable<br />k8s_node_cpu_cores_requests<br />k8s_node_cpu_cores_limits |  The capacity and the Requests / Limits / Allocatable of the CPU  | K8s kube-state-metrics |
| Memory Resources | GB | k8s_node_memory_total<br />k8s_node_memory_allocatable<br />k8s_node_memory_requests<br />k8s_node_memory_limits | The capacity and the Requests / Limits / Allocatable of the memory | K8s kube-state-metrics |
| Storage Resources | GB | k8s_node_storage_total<br />k8s_node_storage_allocatable | The capacity and allocatable of the storage | K8s kube-state-metrics |
| CPU Usage | m | k8s_node_cpu_usage | The CPU cores total usage, if there are 2 cores the max usage is 2000m | cAdvisor |
| Memory Usage | GB | k8s_node_memory_usage | The memory total usage | cAdvisor |
| Network I/O| KB/s | k8s_node_network_receive<br />k8s_node_network_transmit | The Network receive and transmit | cAdvisor |

### Service
In these metrics, the pods are related to the selected service (`Current Endpoint in the dashboard`).

| Monitoring Panel | Unit | Metric Name | Description | Data Source |
|-----|-----|-----|-----|-----|
| Service Pod Total |  | k8s_service_pod_total | The number of the pods | K8s kube-state-metrics |
| Service Pod Status |  | k8s_service_pod_status | The current status of pods | K8s kube-state-metrics |
| Service CPU Resources | m | k8s_service_cpu_cores_requests<br />k8s_service_cpu_cores_limits | The CPU resources Requests / Limits of this service | K8s kube-state-metrics |
| Service Memory Resources | MB | k8s_service_memory_requests<br />k8s_service_memory_limits | The memory resources Requests / Limits of this service | K8s kube-state-metrics |
| Pod CPU Usage | m | k8s_service_pod_cpu_usage | The CPU resources total usage of pods | cAdvisor |
| Pod Memory Usage | MB | k8s_service_pod_memory_usage | The memory resources total usage of pods | cAdvisor |
| Pod Waiting |  | k8s_service_pod_status_waiting | The pods and containers which currently in the waiting status, and show the reason | K8s kube-state-metrics |
| Pod Terminated |  | k8s_service_pod_status_terminated | The pods and containers which currently in the terminated status, and show the reason | K8s kube-state-metrics |
| Pod Restarts |  | k8s_service_pod_status_restarts_total | The number of per container restarts that related to the pod | K8s kube-state-metrics |
| Pod Network Receive | KB/s | k8s_service_pod_network_receive | The Network receive of the pods | cAdvisor |
| Pod Network Transmit | KB/s | k8s_service_pod_network_transmit | The Network transmit of the pods  | cAdvisor |
| Pod Storage Usage | MB | k8s_service_pod_fs_usage | The storage resources total usage of pods which related to this service | cAdvisor |

## Customizing 
You can customize your own metrics/expression/dashboard panel.   
The metrics definition and expression rules are in `/config/otel-oc-rules/k8s-cluster.yaml，/config/otel-oc-rules/k8s-node.yaml, /config/otel-oc-rules/k8s-service.yaml`.  
The dashboard panel confirmations are in `/config/ui-initialized-templates/k8s.yml`.