RISC-V is an open source instruction set architecture (ISA) based on reduced instruction set computing (RISC). openEuler has made some explorations on RISC-V:

[^]: The following information is selected from https://gitee.com/openeuler/RISC-V.

• In June 2020, openEuler released the first version of the root file system (rootfs) and kernel image that supports RISC-V.
• In August 2020, the openEuler RISC-V software package is built using the Open Build Service (OBS).
• In September 2020, Huawei released openEuler RISC-V at HUAWEI CONNECT 2020, the first RISC-V Linux system in China.
• In October 2020, the Chinese Academy of Sciences successfully ported openEuler RISC-V to Nutshell.
• In November 2020, the second version of rootfs and kernel image is released in the openEuler image repository. You can start the image in QEMU and experience the ported openEuler RISC-V.

The container technology has become a new trend, and technology companies are actively embracing containers. How to use QEMU to start the ported openEuler RISC-V and run containers in it? This article may give you an answer.

Environment Requirements ​

• Operating environment: Linux
• Required file: openEuler RISC-V system image. For details, see "Obtaining the Ported openEuler RISC-V System Image" below.
• Software environment: 4.0.0 ≤ QEMU ≤ 5.0.1. For details, see "Obtaining the Ported openEuler RISC-V System Image."

Obtaining the Ported openEuler RISC-V System Image ​

You can obtain the latest openEuler RISC-V image and the REPO source of the ported openEuler RISC-V from the openEuler official website.

https://repo.openeuler.org/openEuler-preview/RISC-V/Image/

The following two files are required for starting the ported openEuler RISC-V:

• fw_payload_oe_docker.elf: image (for QEMU-based startup) built using the kernel-5.5 image as the payload through the Open Source Supervisor Binary Interface (OpenSBI). In addition, it includes Docker-related startup configurations.
• openEuler-preview.riscv64.qcow2: rootfs image of the ported openEuler RISC-V

Starting openEuler RISC-V Using QEMU ​

Ensure that the qemu-system-riscv64 binary program exists in your host Linux environment. If the REPO source of your Linux environment does not provide this binary program, manually build it from the QEMU source code. For details, see the QEMU official guide.

Build QEMU for Platforms/RISCV

The following is an example:

git clone https://gitee.com/openeuler/qemu.git
cd qemu
./configure --target-list=riscv64-softmmu && make
cp riscv64-softmmu/qemu-system-riscv64 /bin

Run the following commands to start QEMU. In this example, the network function is implemented through host port forwarding.

$ qemu-system-riscv64 \
  -nographic -machine virt \
  -smp 8 -m 2G \
  -kernel fw_payload_oe_docker.elf \
  -drive file=openEuler-preview.riscv64.qcow2,format=qcow2,id=hd0 \
  -object rng-random,filename=/dev/urandom,id=rng0 \
  -device virtio-rng-device,rng=rng0 \
  -device virtio-blk-device,drive=hd0 \
  -device virtio-net-device,netdev=usernet \
  -netdev user,id=usernet,hostfwd=tcp::12055-:22 \
  -append 'root=/dev/vda1 rw console=ttyS0 systemd.default_timeout_start_sec=600 selinux=0 highres=off mem=4096M earlycon'

After the system is started, you can log in to the guest OS using an SSH tool and access the Internet in the emulator. The default user name and password for the login are root and openEuler12#$, respectively.

 ssh -p 12055 root@localhost

Deploying runc and Running Containers ​

Note: The following operations are performed on the guest OS, which is openEuler RISC-V, running on an emulator.

Installing the runc Software Package ​

The openEuler RISC-V REPO source contains the runc software package. Run the following commands to configure the REPO source and install runc:

# yum-config-manager --add-repo https://repo.openeuler.org/openEuler-preview/RISC-V/everything/
# yum install docker-runc

Preparing a Container Image ​

1. Prepare a working directory.

   Before the deployment, prepare a working directory, for example, mycontainer. All subsequent operations in this article are performed in this directory.

   shell

   mkdir mycontainer
   cd mycontainer

2. Prepare a container startup image.

   Use a self-made rootfs as the container startup image. If GCC (or other software based on your site requirements) is required in the self-made file system, run the following commands:

   shell

   mkdir rootfs
   yum install gcc --installroot=`pwd`/rootfs

Using runc to Run the Container ​

After rootfs is prepared, you need to generate a config.json file based on the Open Container Initiative (OCI). This file describes how to run a container, including the commands, permissions, and environment variables. runc provides the spec command to generate the configuration file:

[root@openEuler-RISCV-rare mycontainer]# runc spec
[root@openEuler-RISCV-rare mycontainer]# ls
config.json  rootfs

In this way, an OCI runtime bundle is created. The bundle is simple and consists of the config.json file and rootfs. The config.json file contains a large amount of information and no modification is required. Use the file generated by default. With the configuration file and rootfs, you can use runc to run a container. The first method is to run runc run (root permissions required). It creates and starts a container.

[root@openEuler-RISCV-rare mycontainer]# runc run openEuler_container
sh-5.0# ls
bin  boot  dev	etc  home  lib	lib64  media  mnt  opt	proc  root  run  sbin  srv  sys  tmp  usr  var
sh-5.0# whoami
root
sh-5.0# pwd
/
sh-5.0# echo hello container
hello container

The last parameter is the container name, which must be unique on the host. After the container is started, the sh shell of the container is displayed. Since no network settings are configured for the container, it only has a default lo interface and cannot communicate with the external network. Other functions are normal.

In this case, you can open another terminal to view the information about the running container.

[root@openEuler-RISCV-rare ~]# runc list
ID                    PID         STATUS      BUNDLE              CREATED                        OWNER
openEuler_container   17318       running     /home/mycontainer   2019-09-03T15:27:25.5978852Z   root

Another method is to use the specs lifecycle operations to create and manage containers. Directly using this method will start containers in the background. Therefore, before that, modify the config.json file: Change the value of terminal to false and the value of args to sleep 20. The value of args is only an example. You can modify it based on the site requirements.

"process": {
		"terminal": false,
		"consoleSize": {
			"height": 0,
			"width": 0
		},
		"user": {
			"uid": 0,
			"gid": 0
		},
		"args": [
			"sleep", "20"
		],
		···
}

After that, you can use runc to change the status of containers.

1. Run create to create a container. In this case, the container is not running, but all running environments are prepared. Run list to view the container status. The container status is created.

   Assume that the container name is openEuler. Run the following commands:

[root@openEuler-RISCV-rare mycontainer]# runc create openEuler
[root@openEuler-RISCV-rare mycontainer]# runc list
ID          PID         STATUS      BUNDLE              CREATED                        OWNER
openEuler   17402       created     /home/mycontainer   2019-09-03T15:37:46.6289281Z   root

2. Start the container. The startup command sleep 20 is executed. Run list to check the container status. The container is in running state.

[root@openEuler-RISCV-rare mycontainer]# runc start openEuler
[root@openEuler-RISCV-rare mycontainer]# runc list
ID          PID         STATUS      BUNDLE              CREATED                        OWNER
openEuler   17402       running     /home/mycontainer   2019-09-03T15:37:46.6289281Z   root

3. After the container runs for 20 seconds, the container is stopped and is in stop state.

[root@openEuler-RISCV-rare mycontainer]# runc list
ID          PID         STATUS      BUNDLE              CREATED                        OWNER
openEuler   0           stopped     /home/mycontainer   2019-09-03T15:37:46.6289281Z   root

4. After the container is deleted, the container information does not exist.

[root@openEuler-RISCV-rare mycontainer]# runc delete openEuler
[root@openEuler-RISCV-rare mycontainer]# runc list
ID          PID         STATUS      BUNDLE      CREATED     OWNER

For more information about how to use runc, run the runc -h command. openEuler RISC-V Docker will also be enabled in the future. For more information about openEuler RISC-V, visit:

https://gitee.com/openeuler/RISC-V