Maintain ContainerOS nodes using administrative containers or hosts - Container Service for Kubernetes

To mitigate security risks, ContainerOS restricts direct system logon for untraceable operations. For administrative tasks such as troubleshooting and package installation, it provides an administrative container. This topic describes how to perform common administrative operations in ContainerOS, including logon, startup, shutdown, restart, and status query.

ContainerOS O&M methods

Compared with hosts, the administrative container is pre-installed with additional software packages, and allows package installations by using the software package manager YUM. The administrative container displays information about system processes, networks, and system configurations. Additionally, it provides commands to log on to the host from the container. This logon method is similar to logging on to the instance using Workbench, SSH, or VNC.

Starting from ContainerOS 3.5, Shell is removed from the host environment. Refer to the following table to choose how to maintain ContainerOS nodes:

Method

ContainerOS 3.5 and later

ContainerOS earlier than 3.5

Log on to the administrative container

Workbench (secret-free only) logon
VNC logon

Bind an SSH key pair in advance, run sudo lifseacli container start to start the administrative container, and log on through SSH.

The host does not enable SSH by default.

Log on to the host

After logging on to the administrative container, run the sudo superman command.

Workbench (secret-free only) logon
VNC logon

You can also maintain ContainerOS using the kubectl debug command.

Logon methods for administrative containers in ContainerOS 3.5 and later

Category

Workbench (secret-free only) logon

VNC logon

Prerequisites

None.

The Cloud Assistant is pre-installed in the administrative container.

VNC logon requires password authentication. First, you must set the administrative container logon password through the Workbench (secret-free only) logon method.

Procedure

Log on to the ACK console. In the navigation pane on the left, click Clusters.
On the Clusters page, click the name of the one you want to change. In the navigation pane on the left, choose Nodes > Nodes.
In the Actions column of the target node, choose More > Workbench Remote Connection.
Log on using the secret-free connection method.

Log on to the ACK console. In the navigation pane on the left, click Clusters.
On the Clusters page, click the name of the one you want to change. In the navigation pane on the left, choose Nodes > Nodes.
In the Actions column of the target node, choose More > VNC Remote Connection, and follow the page prompts to complete identity authentication.

Host logon methods for ContainerOS earlier than 3.5

Category	Workbench (secret-free only) logon	VNC logon
Prerequisites	Ensure that the node can access the Cloud Assistant service.	VNC logon requires password authentication. First, you must set the administrative container logon password through the Workbench (secret-free only) logon method.
Procedure	Log on to the ACK console. In the navigation pane on the left, click Clusters. On the Clusters page, click the name of the one you want to change. In the navigation pane on the left, choose Nodes > Nodes. In the Actions column of the target node, choose More > Workbench Remote Connection.	Log on to the ACK console. In the navigation pane on the left, click Clusters. On the Clusters page, click the name of the one you want to change. In the navigation pane on the left, choose Nodes > Nodes. In the Actions column of the target node, choose More > VNC Remote Connection, and follow the page prompts to complete identity authentication.

Administrative container startup methods for ContainerOS earlier than 3.5

Preparations

The administrative container only supports key pair logon. After creating a node pool, you must configure the logon mode as Key Pair. For more information, see Create and manage node pools.
Existing node pools can be bound to SSH key pairs.
The ECS Cloud Assistant is installed. For details, see Install Cloud Assistant Agent.
Port 22 is allowed by the security group. For more information, see Manage security group rules.
Log on to the ECS instance using Secret-free login.

Enter the host environment

Log on to ECS console - ECS Cloud Assistant and click Create/Run Command in the upper-right corner of the ECS Cloud Assistant page. For more information, see Create and run a command.
In the Create Command panel, run the following command to start the administrative container:
```
sudo lifseacli container start
```
Expected output:
The output shows that the Cloud Assistant successfully started the administrative container.
Run the following command to log on to the administrative container using the specified private key from a terminal that supports SSH commands:
Note
- Replace <ssh-private-key.pem> with the private key from the key pair bound to the instance, and <instance-ip> with the IP address of the instance.
- Alternatively, you can log on directly as admin using Workbench. The private key is from the key pair that is bound to the instance. Make sure that port 22 on the instance is open.
```
ssh -i <ssh-private-key.pem> admin@<instance-ip>
```
The administrative container interface after successful logon is shown below. The root file system of the host is mounted in read-only mode to the /.lifsea/rootfs directory of the administrative container. You can directly obtain system information and configurations from this directory.
Run the following command to log on to the host from the administrative container:
```
sudo superman
```
Run the ls command to list the available system commands.
Expected output:
The output indicates that the host offers a limited set of system commands.

Administrative container operations

After logging on to the host environment, use the exit command to exit the host environment. Run the exit command once more to exit the administrative container. It's still running and can be reconnected using SSH. Additionally, you can run commands to stop, restart, and delete the administrative container.

Operation	Description
Stop	`sudo lifseacli container stop`
Restart	If you bind a new key pair to or unbind the key pair from the instance after starting the administrative container, you must restart the container for the change to take effect. `sudo lifseacli container restart`
Delete	`sudo lifseacli container rm` Important Deleting the administrative container also removes installed software and saved files. Restarting the container initializes a new environment. Do not save important data in the administrative container.
Query status	`sudo lifseacli container status`

FAQ

What do I do if the error `UNPROTECTED PRIVATE KEY FILE!` occurs when I connect to the administrative container?

Description

An error message is shown in the following figure:

Cause

The private key file is accessible by other users.

Solution

Run the chmod 400 <ssh-private-key.pem> command to adjust the permissions to 400 on the private key file. Replace <ssh-private-key.pem> with the name of your private key file.

Reference

ContainerOS image release notes