Seal your applications all dependencies and kubernetes into CloudImage! Build Deliver and Run user-defined clusters in one command.

pushedAt 1 day ago


Sealer -- Build, Share and Run Any Distributed Applications

License Go Release GoDoc CII Best Practices




sealer[ˈsiːlər] provides the way for distributed application package and delivery based on kubernetes.



  • CloudImage : like Dockerimage, but the rootfs is kubernetes, and contains all the dependencies(docker images,yaml files or helm chart...) your application needs.
  • Kubefile : the file describe how to build a CloudImage.
  • Clusterfile : the config of using CloudImage to run a cluster.


We can write a Kubefile, and build a CloudImage, then using a Clusterfile to run a cluster.

sealer[ˈsiːlər] provides the way for distributed application package and delivery based on kubernetes.

It solves the delivery problem of complex applications by packaging distributed applications and dependencies(like database,middleware) together.

For example, build a dashboard CloudImage:


# base CloudImage contains all the files that run a kubernetes cluster needed.
#    1. kubernetes components like kubectl kubeadm kubelet and apiserver images ...
#    2. docker engine, and a private registry
#    3. config files, yaml, static files, scripts ...
FROM registry.cn-qingdao.aliyuncs.com/sealer-io/kubernetes:v1.19.8
# download kubernetes dashboard yaml file
RUN wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.2.0/aio/deploy/recommended.yaml
# when run this CloudImage, will apply a dashboard manifests
CMD kubectl apply -f recommended.yaml

Build dashobard CloudImage:

sealer build -t registry.cn-qingdao.aliyuncs.com/sealer-io/dashboard:latest .

Run a kubernetes cluster with dashboard:

# sealer will install a kubernetes on host then apply the dashboard manifests
sealer run registry.cn-qingdao.aliyuncs.com/sealer-io/dashboard:latest --masters --passwd xxx
# check the pod
kubectl get pod -A|grep dashboard

Push the CloudImage to the registry

# you can push the CloudImage to docker hub, Ali ACR, or Harbor
sealer push registry.cn-qingdao.aliyuncs.com/sealer-io/dashboard:latest

Usage scenarios & features

  • An extremely simple way to install kubernetes and other software in the kubernetes ecosystem in a production or offline environment.
  • Through Kubefile, you can easily customize the kubernetes CloudImage to package the cluster and applications, and submit them to the registry.
  • Powerful life cycle management capabilities, to perform operations such as cluster upgrade, cluster backup and recovery, node expansion and contraction in unimaginable simple ways
  • Very fast, complete cluster installation within 3 minutes
  • Support ARM x86, v1.20 and above versions support containerd, almost compatible with all Linux operating systems that support systemd
  • Does not rely on ansible haproxy keepalived, high availability is achieved through ipvs, takes up less resources, is stable and reliable
  • Many ecological software images can be used directly, like prometheus mysql..., and you can combine then together.

Quick start

Install a kubernetes cluster

#install Sealer binaries
wget https://github.com/alibaba/sealer/releases/download/v0.6.1/sealer-v0.6.1-linux-amd64.tar.gz && \
tar zxvf sealer-v0.6.1-linux-amd64.tar.gz && mv sealer /usr/bin
#run a kubernetes cluster
sealer run kubernetes:v1.19.8 --masters --passwd xxx

User guide

get started

Developing Sealer


Sealer is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

ucloud ads