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operations/system_management_health/victoriametrics.md

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+# VictoriaMetrics
+
+VictoriaMetrics is a fast, cost-effective, and scalable time series database. It can be used as a long-term remote storage for Prometheus.
+
+It is recommended to use the single-node version instead of the cluster version for ingestion rates lower than a million data points per second. The single-node version scales perfectly with the number of CPU cores, RAM, and available storage space.
+
+## Prominent features
+
+- Supports all the features of the single-node version.
+- Performance and capacity scale horizontally.
+- Supports multiple independent namespaces for time series data (aka multi-tenancy).
+- Supports replication.
+
+## Architecture overview
+
+![Prometheus architecture with Thanos](../../img/operations/Prometheus_with_thanos_architecture.png "Prometheus architecture with Thanos")
+
+VictoriaMetrics cluster consists of the following services:
+
+**Vmstorage:** It stores the raw data and returns the queried data on the given time range for the given label filters. This is the only stateful component in the cluster.
+
+**Vminsert:** It accepts the ingested data and spreads it among vmstorage nodes according to consistent hashing over metric name and all its labels.
+
+**Vmselect:** It performs incoming queries by fetching the needed data from all the configured vmstoragenodes.
+To access vmselect GUI, use `ssh` port-forwarding.
+
+1. Use `kubectl` command to get the `SERVICE-IP` of `vmselect-vms` service.
+
+ ```yaml
+ kubectl get service -n sysmgmt-health vmselect-vms
+ ```
+
+ Expected output looks similar to the following:
+
+ ```text
+ NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
+ vmselect-vms ClusterIP None <none> 8481/TCP 122d
+ ```
+
+2. Use `vmselect-vms` service name and `8481` port number to port forward.
+
+ ```text
+ kubectl port-forward -n sysmgmt-health service/vmselect-vms 8481:8481
+ ``` 
+
+3. Use local laptop or desktop command line to access the cluster.
+
+Use `ssh` port-forwarding using the service IP.
+
+ ```text
+ ssh -L 8481:localhost:8481 root@SYSTEM-IP
+ ```
+
+3. Open `http://localhost:8481/select/0/prometheus/vmui/` in the browser to access the GUI.
+
+NOTE: `10.11.12.13` and `SYSTEM-IP` is the IP Address of the host system.
+
+**Vmagent:** It is a tiny but mighty agent which helps you collect metrics from various sources and store them in VictoriaMetrics or any other Prometheus-compatible storage systems that support the remote_write protocol.
+
+To access vmagent GUI, use `ssh` port-forwarding.
+
+1. Use `kubectl` command to get the `SERVICE-IP` of `cray-sysmgmt-health-thanos-query` service.
+
+ ```yaml
+ kubectl get svc -n sysmgmt-health vmagent-vms
+ ```
+
+ Expected output looks similar to the following:
+
+ ```text
+ NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
+ vmagent-vms ClusterIP 10.17.40.41 <none> 8429/TCP 6d5h
+ ```
+
+2. Use `ssh` port-forwarding using the service IP.
+
+ ```text
+ ssh root@SYSTEM-IP -L 9090:SERVICE-IP:9090
+ ```
+
+3. Open `localhost:8429` in the browser to access the GUI.
+
+NOTE: In this case `SERVICE-IP` is `10.11.12.13` and `SYSTEM-IP` is the IP Address of the host system.
+
+
+**Vmalert:** It executes a list of the given alerting or recording rules against configured data sources. Sending alerting notifications vmalert relies on configured Alertmanager. 
+Recording rules results are persisted via remote write protocol. vmalert is heavily inspired by Prometheus implementation and aims to be compatible with its syntax.
+
+Each service may scale independently and may run on the most suitable hardware. vmstorage nodes do not know about each other, do not communicate with each other and don’t share any data. 
+This is a shared nothing architecture. It increases cluster availability, and simplifies cluster maintenance as well as cluster scaling.
+
+## Cluster resizing and scalability
+
+Cluster performance and capacity can be scaled up in two ways:
+
+- Vertical scalability: Adding more resources (CPU, RAM, disk IO, disk space, and so on).
+- Horizontal scalability: Adding more of each component to the cluster.