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Frequently Asked Questions

When using Sealos, you may encounter some common questions and issues. Here are answers and solutions to some of the common problems.

Image Building Issues

Q1: How to set up a proxy service during the build phase?

During the execution of the build command, you can configure a proxy service by setting the HTTP_PROXY environment variable.

HTTP_PROXY=socket5:// sealos build xxxxx

Q2: How to enable debug logs for buildah?

To view debug logs for buildah, you can set the BUILDAH_LOG_LEVEL environment variable.

BUILDAH_LOG_LEVEL=debug sealos images

Q3: How to execute Sealos build within a Pod?

If you want to execute Sealos build within a Pod, follow these steps:

  1. Build the image within the Pod. You can create a Deployment with the following YAML configuration:
apiVersion: apps/v1
kind: Deployment
app: sealoscli
name: sealoscli
replicas: 1
app: sealoscli
strategy: {}
app: sealoscli
- image: # Replace with your sealos image
name: sealoscli
stdin: true
stdinOnce: true
privileged: true
  1. Create a Dockerfile. Here's an example that you can modify as per your needs:
FROM bitnami/minideb:buster


LABEL from=bitnami/minideb:buster platform=rootcloud team=oam tag=buster name=base

RUN sed -i "s@" /etc/apt/sources.list && sed -i "s@" /etc/apt/sources.list
RUN install_packages curl iputils-ping net-tools telnet procps vim wget jq

ENV TZ=Asia/Shanghai
  1. Execute the build command within the Pod.
sealos build --arch arm64 --build-arg TARGETOS=linux --build-arg TARGETARCH=arm64 -t test  -f Dockerfile .

Q4: How to Build Cluster Images Using Other Build Tools?

If you want to use other container tools like Docker or Podman to build cluster images, you can utilize sreg to cache the images.

Follow these steps:

  1. Install sreg:
    tar -xzf sreg_0.1.1_linux_amd64.tar.gz sreg
    mv sreg /usr/bin/
  2. Cache the images:
    sreg save --registry-dir=registry .
  3. Build the cluster image:
    docker build -t xxxx -f Sealfile .

Q5: Encounter the error "lgetxattr /var/lib/containers/storage/overlay/0c2afe770ec7870ad4639f18a1b50b3a84718f95c8907f3d54e14dbf0a01d50d/merged/dev/ptmx: no such device" during Sealos build. How to fix it?

This issue might be related to the version of fuse-overlayfs. We recommend downloading the latest version from here and replacing /bin/fuse-overlayfs.

Runtime Selection Issues

Q1: How to select the Kubernetes runtime?

Sealos determines the runtime based on the image you choose. If you select the kubernetes-docker image, Sealos will use Docker as the runtime. If you choose the kubernetes-crio image, Sealos will use CRI-O as the runtime.

Version Compatibility Issues

Q1: Error "Applied to cluster error: failed to

init exec failed exit status 127"?

This error is often caused by a mismatch between the version of Sealos and the version of the image being used. Make sure that the image version and the Sealos version are compatible. For example, if you are using a Kubernetes version like v1.xx.x, you may need to upgrade Sealos, especially if you are using an older version of Sealos while the Sealos cluster image is using the latest version. Another solution is to choose the corresponding version of the Sealos image. For example, if your Sealos version is 4.1.3, then the cluster image should be something like kubernetes:v1.24.0-4.1.3. Ensuring that the image version and Sealos version are compatible can help avoid such issues.

Q2: Error when adding additional domains or modifying the service CIDR in the cluster during the addition of a master node

To address this issue, the Sealos team made the necessary fixes in version 4.2.0. You can refer to the specific fix and discussion in this pull request:

Therefore, if you encounter this problem, we recommend upgrading to Sealos version 4.2.0. The updated version should handle these changes correctly and not produce errors when adding a master node.

File and Directory Location Issues

Q1: How to modify the default storage location for /root/.sealos?

If you need to change the default storage location, you can set the SEALOS_RUNTIME_ROOT environment variable and then run the Sealos command. It is recommended to set this environment variable globally so that it can be conveniently used in other commands or scenarios.

export SEALOS_RUNTIME_ROOT=/data/.sealos 
sealos run labring/kubernetes:v1.24.0

Q2: How to modify the default storage location for /var/lib/sealos?

If you need to change the default storage location, you can set the SEALOS_DATA_ROOT environment variable and then run the Sealos command. Similarly, it is recommended to set this environment variable globally.

export SEALOS_DATA_ROOT=/data/sealos 
sealos run labring/kubernetes:v1.24.0

Q3: How to modify the storage paths for Sealos image data and status?

When using the Sealos cluster, you may need to change the default storage paths for image data and status data. By default, these data are stored at the locations defined in the /etc/containers/storage.conf file.

  1. View the current storage configuration First, you can use the following command to view the current image storage configuration:
    sealos images --debug
    This command will print the file that contains the current storage configuration, for example:
    2023-06-07T16:27:02 debug using file /etc/containers/storage.conf as container storage config
  2. Modify the storage path for image data If you want to change the storage path for image data, you can edit the /etc/containers/storage.conf file. In this file, find and modify the graphroot field to set it to the new path. For example:
    vim /etc/containers/storage.conf
    In the editor, modify the value of the graphroot field to the desired new path.
  3. **Modify the storage

path for status data** Similar to the design of Buildah, Sealos also provides the ability to set the storage path for status data. In the same configuration file /etc/containers/storage.conf, find and modify the runroot field to the new path.

By following these steps, you can save the image data and status data of the Sealos cluster to the new paths you set. Each time you run a Sealos command, it will use the new paths you set in graphroot and runroot to store the image data and status data, respectively.

Q4: How to disable file md5 check during SSH file transfer?

When the network environment is good, disabling the md5 check can greatly improve transfer speed. If you don't want to check the md5 of files during SSH file transfer, you can add the -o "HashKnownHosts no" option to the SSH command.

scp -o "HashKnownHosts no" local_file remote_user@remote_ip:/path/to/destination

This option tells SSH not to hash the hostnames in the known_hosts file, which avoids the md5 check during file transfer.