sidekick is a high-performance sidecar load balancer. By attaching a tiny load balancer to each client application process, you can eliminate the need for a centralized load balancer and DNS failover management. sidekick automatically avoids sending traffic to the failed servers by checking their health via the readiness API and HTTP error returns.

Architecture

Install

Binary Releases

OS	ARCH	Binary
Linux	amd64	linux-amd64
Linux	arm64	linux-arm64
Linux	ppc64le	linux-ppc64le
Linux	s390x	linux-s390x
Apple	amd64	darwin-amd64
Windows	amd64	windows-amd64

You can also verify the binary with minisign by downloading the corresponding .minisig signature file. Then run:

minisign -Vm sidekick-<OS>-<ARCH> -P RWTx5Zr1tiHQLwG9keckT0c45M3AGeHD6IvimQHpyRywVWGbP1aVSGav

Docker

Pull the latest release via:

docker pull quay.io/minio/sidekick:v7.0.0

Build from source

go install -v github.com/minio/sidekick@latest

Important

You will need a working Go environment. Therefore, please follow How to install Go. The minimum version required is go1.22

Usage

NAME:
  sidekick - High-Performance sidecar load-balancer

USAGE:
  sidekick - [FLAGS] SITE1 [SITE2..]

FLAGS:
  --address value, -a value           listening address for sidekick (default: ":8080")
  --health-path value, -p value       health check path
  --read-health-path value, -r value  health check path for read access - valid only for failover site
  --health-port value                 health check port (default: 0)
  --health-duration value, -d value   health check duration in seconds (default: 5s)
  --health-timeout value              health check timeout in seconds (default: 10s)
  --insecure, -i                      disable TLS certificate verification
  --rr-dns-mode                       enable round-robin DNS mode
  --log, -l                           enable logging
  --trace value, -t value             enable request tracing - valid values are [all,application,minio] (default: "all")
  --quiet, -q                         disable console messages
  --json                              output sidekick logs and trace in json format
  --debug                             output verbose trace
  --cacert value                      CA certificate to verify peer against
  --client-cert value                 client certificate file
  --client-key value                  client private key file
  --cert value                        server certificate file
  --key value                         server private key file
  --pprof :1337                       start and listen for profiling on the specified address (e.g. :1337)
  --dns-ttl value                     choose custom DNS TTL value for DNS refreshes for load balanced endpoints (default: 10m0s)
  --errors, -e                        filter out any non-error responses
  --status-code value                 filter by given status code
  --host-balance value                specify the algorithm to select backend host when load balancing, supported values are 'least', 'random' (default: "least")
  --help, -h                          show help
  --version, -v                       print the version

Examples

Load balance across a web service using DNS provided IPs.

$ sidekick --health-path=/ready http://myapp.myorg.dom

Load balance across 4 MinIO Servers.

http://minio1:9000 to http://minio4:9000

$ sidekick --health-path=/minio/health/ready --address :8000 http://minio{1...4}:9000

Load balance across two sites with four servers each

$ sidekick --health-path=/minio/health/ready http://site1-minio{1...4}:9000 http://site2-minio{1...4}:9000

Realworld Example with spark-operator

With spark as driver and sidecars as executor, first install spark-operator and MinIO on your Kubernetes cluster.

Configure spark-operator

This guide uses the maintained spark operator by GCP at https://github.com/GoogleCloudPlatform/spark-on-k8s-operator.

helm repo add spark-operator https://googlecloudplatform.github.io/spark-on-k8s-operator
helm --namespace spark-operator install spark-operator spark-operator/spark-operator --create-namespace --set sparkJobNamespace=spark-operator --set enableWebhook=true

Install MinIO.

Ensure that the standard storage class was previously installed. Note that TLS is disabled for this test. Note also that the minio tenant created is called myminio.

helm repo add minio-operator https://operator.min.io/
helm install operator minio-operator/operator --namespace minio-operator --create-namespace
  
helm install myminio minio-operator/tenant --namespace tenant-sidekick --create-namespace && \
kubectl --namespace tenant-sidekick patch tenant myminio --type='merge' -p '{"spec":{"requestAutoCert":false}}'

Once the tenant pods are running, port-forward the minio headless service to access it locally.

kubectl --namespace tenant-sidekick port-forward svc/myminio-hl 9000 &

Configure mc and upload some data. Use mybucket as the s3 bucket name. Create bucket named mybucket and upload some text data for spark word count sample.

mc alias set myminio http://localhost:9000 minio minio123
mc mb myminio/mybucket
mc cp /etc/hosts myminio/mybucket/mydata.txt

Run the spark job in k8s

Obtain the IP address and port of the minio service. Use them as input to fs.s3a.endpoint the below SparkApplication. e.g. http://10.43.141.149:80

kubectl --namespace tenant-sidekick get svc/minio

Create the spark-minio-app yml

cat << EOF > spark-job.yaml
apiVersion: "sparkoperator.k8s.io/v1beta2"
kind: SparkApplication
metadata:
  name: spark-minio-app
  namespace: spark-operator
spec:
  sparkConf:
    spark.kubernetes.allocation.batch.size: "50"
  hadoopConf:
    "fs.s3a.endpoint": "http://10.43.141.149:80"
    "fs.s3a.access.key": "minio"
    "fs.s3a.secret.key": "minio123"
    "fs.s3a.path.style.access": "true"
    "fs.s3a.impl": "org.apache.hadoop.fs.s3a.S3AFileSystem"
  type: Scala
  sparkVersion: 2.4.5
  mode: cluster
  image: minio/spark:v2.4.5-hadoop-3.1
  imagePullPolicy: Always
  restartPolicy:
      type: OnFailure
      onFailureRetries: 3
      onFailureRetryInterval: 10
      onSubmissionFailureRetries: 5
      onSubmissionFailureRetryInterval: 20
  mainClass: org.apache.spark.examples.JavaWordCount
  mainApplicationFile: "local:///opt/spark/examples/target/original-spark-examples_2.11-2.4.6-SNAPSHOT.jar"
  arguments:
  - "s3a://mybucket/mydata.txt"
  driver:
    cores: 1
    memory: "512m"
    labels:
      version: 2.4.5
    sidecars:
    - name: minio-lb
      image: "quay.io/minio/sidekick:v4.0.3"
      imagePullPolicy: Always
      args: ["--health-path", "/minio/health/ready", "--address", ":8080", "http://myminio-pool-0-{0...3}.myminio-hl.tenant-sidekick.svc.cluster.local:9000"]
      ports:
        - containerPort: 9000
          protocol: http
  executor:
    cores: 2
    instances: 4
    memory: "1024m"
    labels:
      version: 2.4.5
    sidecars:
    - name: minio-lb
      image: "quay.io/minio/sidekick:v4.0.3"
      imagePullPolicy: Always
      args: ["--health-path", "/minio/health/ready", "--address", ":8080", "http://myminio-pool-0-{0...3}.myminio-hl.tenant-sidekick.svc.cluster.local:9000"]
      ports:
        - containerPort: 9000
          protocol: http
EOF

Grant permissions to access resources to the service account

kubectl create clusterrolebinding spark-role --clusterrole=edit --serviceaccount=spark-operator:default --namespace=spark-operator
kubectl create -f spark-job.yaml
kubectl --namespace spark-operator logs -f spark-minio-app-driver

Monitor

The above SparkApplication will not complete until the Health check returns "200 OK", in this case, when there is a MinIO read quorum. The Health check is provided at the path "/v1/health." It returns "200 OK" even if any one of the sites is reachable; otherwise, it returns a "502 Bad Gateway" error.