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Monitoring

JuiceFS provides a Prometheus API for each file system (the default API address is http://localhost:9567/metrics), which can be used to collect JuiceFS monitoring metrics. Once the monitoring metrics are collected, they can be quickly displayed via the Grafana dashboard template provided by JuiceFS.

Collecting monitoring metrics

There are different ways to collect monitoring metrics depending on how JuiceFS is deployed, which are described below.

Mount point

When the JuiceFS file system is mounted via the juicefs mount command, you can collect monitoring metrics via the address http://localhost:9567/metrics, or you can customize it via the --metrics option. For example:

$ juicefs mount --metrics localhost:9567 ...

You can view these monitoring metrics using the command line tool:

$ curl http://localhost:9567/metrics

In addition, the root directory of each JuiceFS file system has a hidden file called .stats, through which you can also view monitoring metrics. For example (assuming here that the path to the mount point is /jfs):

$ cat /jfs/.stats

Kubernetes

The JuiceFS CSI Driver will provide monitoring metrics on the 9567 port of the mount pod by default, or you can customize it by adding the metrics option to the mountOptions (please refer to the CSI Driver documentation for how to modify mountOptions), e.g.:

apiVersion: v1
kind: PersistentVolume
metadata:
name: juicefs-pv
labels:
juicefs-name: ten-pb-fs
spec:
...
mountOptions:
- metrics=0.0.0.0:9567

Add a crawl job to prometheus.yml to collect monitoring metrics:

scrape_configs:
- job_name: 'juicefs'
kubernetes_sd_configs:
- role: pod
relabel_configs:
- source_labels: [__meta_kubernetes_pod_label_app_kubernetes_io_name]
action: keep
regex: juicefs-mount
- source_labels: [__address__]
action: replace
regex: ([^:]+)(:\d+)?
replacement: $1:9567
target_label: __address__
- source_labels: [__meta_kubernetes_pod_node_name]
target_label: node
action: replace

Here assume the Prometheus server is running inside Kubernetes cluster, if your Prometheus server is running outside Kubernetes cluster, make sure Kubernetes cluster nodes are reachable from Prometheus server, refer to this issue to add the api_server and tls_config client auth to the above configuration like this:

scrape_configs:
- job_name: 'juicefs'
kubernetes_sd_configs:
- api_server: <Kubernetes API Server>
role: pod
tls_config:
ca_file: <...>
cert_file: <...>
key_file: <...>
insecure_skip_verify: false
relabel_configs:
...

S3 Gateway

note

This feature needs to run JuiceFS client version 0.17.1 and above.

The JuiceFS S3 Gateway will provide monitoring metrics at the address http://localhost:9567/metrics by default, or you can customize it with the -metrics option. For example:

$ juicefs gateway --metrics localhost:9567 ...

If you are deploying JuiceFS S3 Gateway in Kubernetes, you can refer to the Prometheus configuration in the Kubernetes section to collect monitoring metrics (the difference is mainly in the regular expression for the label __meta_kubernetes_pod_label_app_kubernetes_io_name), e.g.:

scrape_configs:
- job_name: 'juicefs-s3-gateway'
kubernetes_sd_configs:
- role: pod
relabel_configs:
- source_labels: [__meta_kubernetes_pod_label_app_kubernetes_io_name]
action: keep
regex: juicefs-s3-gateway
- source_labels: [__address__]
action: replace
regex: ([^:]+)(:\d+)?
replacement: $1:9567
target_label: __address__
- source_labels: [__meta_kubernetes_pod_node_name]
target_label: node
action: replace

Collected via Prometheus Operator

Prometheus Operator enables users to quickly deploy and manage Prometheus in Kubernetes, with the help of the ServiceMonitor CRD provided by Prometheus Operator can automatically generate scrape configuration. For example (assuming that the Service of the JuiceFS S3 Gateway is deployed in the kube-system namespace):

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: juicefs-s3-gateway
spec:
namespaceSelector:
matchNames:
- kube-system
selector:
matchLabels:
app.kubernetes.io/name: juicefs-s3-gateway
endpoints:
- port: metrics

For more information about Prometheus Operator, please check official document.

Hadoop

The JuiceFS Hadoop Java SDK supports reporting monitoring metrics to Pushgateway and then letting Prometheus scrape the metrics from Pushgateway.

Please enable metrics reporting with the following configuration:

<property>
<name>juicefs.push-gateway</name>
<value>host:port</value>
</property>

At the same time, the frequency of reporting metrics can be modified through the juicefs.push-interval configuration. The default is to report once every 10 seconds. For all configurations supported by JuiceFS Hadoop Java SDK, please refer to documentation.

info

According to the suggestion of Pushgateway official document, Prometheus's scrape configuration needs to set honor_labels: true.

It is important to note that the timestamp of the metrics scraped by Prometheus from Pushgateway is not the time when the JuiceFS Hadoop Java SDK reported it, but the time when it was scraped. For details, please refer to Pushgateway official document.

By default, Pushgateway will only save metrics in memory. If you need to persist to disk, you can specify the file path for saving with the --persistence.file option and the frequency of saving to the file with the --persistence.interval option (the default save time is 5 minutes).

note

Each process using JuiceFS Hadoop Java SDK will have a unique metric, and Pushgateway will always remember all the collected metrics, resulting in the continuous accumulation of metrics and taking up too much memory, which will also slow down Prometheus scrapes metrics. It is recommended to clean up metrics on Pushgateway regularly.

Regularly use the following command to clean up the metrics of Pushgateway. Clearing the metrics will not affect the running JuiceFS Hadoop Java SDK to continuously report data. Note that the --web.enable-admin-api option must be specified when Pushgateway is started, and the following command will clear all monitoring metrics in Pushgateway.

$ curl -X PUT http://host:9091/api/v1/admin/wipe

For more information about Pushgateway, please check official document.

Use Consul as registration center

note

This feature needs to run JuiceFS client version 1.0.0 and above.

JuiceFS support use Consul as registration center for metrics API. The default Consul address is 127.0.0.1:8500. You could custom the address through --consul option, e.g.:

$ juicefs mount --consul 1.2.3.4:8500 ...

When the Consul address is configured, the --metrics option does not need to be configured. JuiceFS will automatically configure metrics URL according to its own network and port conditions. If --metrics is set at the same time, it will first try to listen on the configured metrics URL.

For each instance registered to Consul, its serviceName is juicefs, and the format of serviceId is <IP>:<mount-point>, for example: 127.0.0.1:/tmp/jfs.

The meta of each instance contains two aspects: hostname and mountpoint. When mountpoint is s3gateway, which means that the instance is an S3 gateway.

Display monitoring metrics

Grafana dashboard template

JuiceFS provides some dashboard templates for Grafana, which can be imported to show the collected metrics in Prometheus. The dashboard templates currently available are:

NameDescription
grafana_template.jsonFor show metrics collected from mount point, S3 gateway (non-Kubernetes deployment) and Hadoop Java SDK
grafana_template_k8s.jsonFor show metrics collected from Kubernetes CSI Driver and S3 gateway (Kubernetes deployment)

A sample Grafana dashboard looks like this:

JuiceFS Grafana dashboard

Monitoring metrics reference

Please refer to the "JuiceFS Metrics" document.