I am attempting to debug some C# / .NET 5 code in WSL 2 with Ubuntu on Windows. I have WSL 2 setup with Windows 10 and want to test out creating a Systemd service. Unfortunately, it appears Systemd is not enabled with WSL 2 by default, even though a standard Ubuntu install does have it enabled by default. Is there any way to get Systemd enabled in WSL 2?
Note: See footnote at bottom of this answer for background on this Community Wiki.
There are several possible paths to enabling Systemd on WSL2 (but not WSL1). These are summarized here, with more detail provided below.
Option 1: Upgrade WSL to the latest application release (if supported by your system) and opt-in to the Systemd feature
Option 2: Run a Systemd-helper script designed for WSL2
Option 3: Manually run Systemd in its own namespace
And while not part of this question, for those simply looking to run certain applications that require Systemd, there are alternatives:
On WSL1 and WSL2:
Alternative 1: SysVInit scripts (e.g. sudo service <service_name> start) where available
Alternative 2: Manually configuring and running the service
On WSL2-only:
Alternative 3: Docker
Should you enable Systemd in WSL?
First, consider whether you should or need to enable Systemd in WSL. Enabling Systemd will automatically start a number of background services and tasks that you really may not need under WSL. As a result, it will also increase WSL startup times, although the impact will be dependent on your system. Check the Alternatives section below to see if there may be a better option that fits your needs. For example, the service command may do what you need without any additional effort.
More detail on each answer:
Option 1: Upgrade WSL to the latest application release (if supported by your system) and opt-in to the Systemd feature
Microsoft has now integrated Systemd support in the WSL2 application release (as opposed to the older "Windows feature" implementation).
Starting with WSL Application Release 1.0.0, this feature is available on both Windows 10 and Windows 11. Windows 10 users do need to be on UBR (update build revision) 2311 or later. The UBR is the last 4 digits of your full Windows build number (e.g. 10.0.19045.2311 for Windows 10 22H2). 2311 is installed with KB5020030, an optional Preview update, although if you are reading this later, it will likely be a later (non-Preview) monthly servicing update.
If you are on a supported Windows release, the WSL application with Systemd support can be installed:
Through the Microsoft Store (as "Windows Subsystem for Linux").
Or from the Releases page in the Github repo. To install a release manually:
Reboot (to make sure that WSL is not in use at all). A simple wsl --shutdown may work, but often will not.
Download the 1.0.0 (or later) release from the link above.
Start an Administrator PowerShell and:
Add-AppxPackage <path.to>/Microsoft.WSL_1.0.0.0_x64_ARM64.msixbundle
wsl --version # to confirm
To enable, start your Ubuntu (or other Systemd) distribution under WSL (typically just wsl ~ will work).
sudo -e /etc/wsl.conf
Add the following:
[boot]
systemd=true
Exit Ubuntu and again:
wsl --shutdown
Then restart Ubuntu.
sudo systemctl status
... should show your Systemd services.
Option 2: Run a Systemd-helper script designed for WSL2
There are a number of Systemd-enablement scripts available from various sources. Given the complexities involved in running Systemd under WSL, it is recommended that you:
Use one that is actively maintained
Attempt to understand, as much as possible, how they operate, and how they may impact other features and applications in your distribution(s) under WSL
When asking questions here or on any other site, disclose in the question which script you are using so that others can attempt to understand and/or reproduce your issue in the proper context
Several of the more popular projects that enable Systemd under WSL2 are:
Genie: 1.8k stars, last commit September, 2022
Distrod: 1.4k stars, last commit July 2022
WSL2-Hacks: 1.1k stars, mostly instructional, with a supporting script example. Last commit January, 2022
At the core, all of them operate on the same principles covered in the next option ...
Option 3: Manually run Systemd in its own namespace
One of the main issues with running Systemd in earlier versions of WSL is that both inits need to be PID 1. To get around this, it is possible to create a new namespace or container where Systemd can run as PID 1.
To see how this is done (at a very basic level):
Run:
sudo -b unshare --pid --fork --mount-proc /lib/systemd/systemd --system-unit=basic.target
This starts Systemd in a new namespace with its own PID mapping. Inside that namespace, Systemd will be PID1 (as it must, to function) and own all other processes. However, the "real" PID mapping still exists outside that namespace.
Note that this is a "bare minimum" command-line for starting Systemd. It will not have support for, at least:
Windows Interop (the ability to run Windows .exe)
The Windows PATH (which isn't necessary without Windows Interop anyway)
WSLg
The scripts and projects listed above do extra work to get these things working as well.
Wait a few seconds for Systemd to start up, then:
sudo -E nsenter --all -t $(pgrep -xo systemd) runuser -P -l $USER -c "exec $SHELL"
This enters the namespace, and you can now use ps -efH to see that systemd is running as PID 1 in that namespace.
At this point, you should be able to run systemctl.
And after proving to yourself that it's possible, it is recommended that you exit all WSL instances completely, then doing wsl --shutdown. Otherwise, some things will be "broken" until you do. They can likely be "fixed", but that's beyond the scope this answer. If you are interested, please refer to the projects listed above to see how they handle these situations.
Alternative 1: SysVInit scripts (e.g. sudo service <service_name> start) where available
In Ubuntu, Debian, and some other distributions on WSL, many of the common system services still have the "old" init.d scripts available to be used in place of systemctl with Systemd units. You can see these by using ls /etc/init.d/.
So, for example, you can start ssh with sudo service ssh start, and it will run the /etc/init.d/ssh script with the start argument.
Even some non-default packages such as MySql/MariaDB will install both the Systemd unit files and the old init.d scripts, so you can still use the service command for them as well.
On the hand, some packages, like Elasticsearch, only install Systemd units. And some distributions only provide Systemd units for most (if not all) packages in their repositories.
Alternative 2: Manually configuring and running the service
For those services that don't have a init-script equivalent, it can be possible to run them "manually".
For simplicity, let's assume that the ssh init.d script wasn't available.
In this case, the "answer" is to figure out what the Systemd unit files are doing and attempt to replicate that manually. This can vary widely in complexity. But I'd start with looking at the Systemd unit file that you are trying to run:
less /lib/systemd/system/ssh.service
# Trimmed
[Service]
EnvironmentFile=-/etc/default/ssh
ExecStartPre=/usr/sbin/sshd -t
ExecStart=/usr/sbin/sshd -D $SSHD_OPTS
RuntimeDirectory=sshd
RuntimeDirectoryMode=0755
Some of the less relevant lines have been trimmed to make it easier to parse, but you can man systemd.exec, man systemd.service, and others to see what most of the options do.
In this case, when you sudo systemctl start ssh, it:
Reads environment variables (the $SSHD_OPTS) from /etc/default/ssh
Tests the config, exits if there is a failure
Makes sure the RuntimeDirectory exists with the specified permissions. This translates to /run/sshd (from man systemd.exec). This also removes the runtime directory when you stop the service.
Runs /usr/sbin/sshd with options
So, if you don't have any environment-based config, you could just set up a script to:
Make sure the runtime directory exists. Note that, since it is in /run, which is a tmpfs mount, it will be deleted after every restart of the WSL instance.
Set the permissions to 0755
Start /usr/sbin/sshd as root
... And you would have done the same thing manually without Systemd.
Again, this is probably the simplest example. You might have much more to work through for more complex tasks.
Alternative 3: Docker
Many packages/services are available as Docker images. Docker typically runs very well under Ubuntu on WSL2 (specifically WSL2; it will not run on WSL1). If there's not a SysVinit "service" script for the service you are trying to start, there may very well be a Docker image available that runs in a containerized environment.
Example: Elasticsearch, as in this question.
Bonus #1: Doesn't interfere with other packages already installed (no dependency issues).
Bonus #2: The Docker images themselves pretty much never use Systemd, so you can often inspect the Dockerfile to see how the service is started without Systemd. For more information see the next option - "The manual way."
Microsoft recommends Docker Desktop for Windows for running Docker containers under WSL2.
Footnote This answer is being posted as a Community Wiki because it can apply to multiple Stack Overflow questions. It is originally based on answers to this Ask Ubuntu question. However, it is hoped that this wiki-answer can be continuously updated by the community as Systemd evolves on WSL.
This question has been chosen since:
It appears to be the most canonical, straightforward, "How do I enable Systemd on WSL?" question.
It is on-topic, as *creating Systemd services is (or at least can-be) unique to programming.
I am installing mongodb in a debian machine but when i end the process and after that put the next command systemctl status mongod, the result is:
So What can I do to revolv the error?
Thanks a lot.
I am trying to installa graylog system but I am sttoped with this error in mongo db...
The failure was signal ILL:
Illegal instruction. The ILL signal is sent to a process when it attempts to execute a malformed, unknown, or privileged instruction.
Starting with version 5.0 MongoDB requires that the CPU support the Advanced Vector Extensions.
The machine you are attempting to start mongod on does not support AVX. You will need to either use a different computer, or downgrade to mongodb version 4.4 or earlier.
I'm currently testing OS and version upgrades for a ceph cluster. Starting info:
The cluster is currently on Centos 7 and Ceph version Nautilus. I'm trying to change OS with ubuntu 20.04 and version with Octopus. I started with upgrading mon1 first. I will write down the things done in order.
First of I stopped monitor service - systemctl stop ceph-mon#mon1
Then I removed the monitor from cluster - ceph mon remove mon1
Then installed ubuntu 20.04 on mon1. Updated the system and configured ufw.
Installed ceph octopus packages.
Copied ceph.client.admin.keyring and ceph.conf to mon1 /etc/ceph/
Copied ceph.mon.keyring to mon1 to a temporary folder and changed ownership to ceph:ceph
Got the monmap ceph mon getmap -o ${MONMAP} - The thing is i did this after removing the monitor.
Created /var/lib/ceph/mon/ceph-mon1 folder and changed ownership to ceph:ceph
Created the filesystem for monitor - sudo -u ceph ceph-mon --mkfs -i mon1 --monmap /folder/monmap --keyring /folder/ceph.mon.keyring
After noticing I got the monmap after the monitors removal I added it manually - ceph mon add mon1 <ip> --fsid <fsid>
After starting manually and checking cluster state with ceph -s I can see mon1 is listed but is not in quorum. The monitor daemon runs fine on the said mon1 node. I noticed on logs that mon1 is stuck in "probe" state and on other monitor logs there is an output such as mon1 (rank 2) addr [v2:<ip>:3300/0,v1:<ip>:6789/0] is down (out of quorum) , as i said the the monitor daemon is running on mon1 without any visible errors just stuck in probe state.
I wondered if it was caused by os&version change so i first tried out configuring manager, mds and radosgw daemons by creating the respective folders in /var/lib/ceph/... and copying keyrings. All these services work fine, i was able to reach to my buckets, was able to open the Octopus version dashboard, and metadata server is listed as active in ceph -s. So evidently my problem is only with monitor configuration.
After doing some checking found this on red hat ceph documantation:
If the Ceph Monitor is in the probing state longer than expected, it
cannot find the other Ceph Monitors. This problem can be caused by
networking issues, or the Ceph Monitor can have an outdated Ceph
Monitor map (monmap) and be trying to reach the other Ceph Monitors on
incorrect IP addresses. Alternatively, if the monmap is up-to-date,
Ceph Monitor’s clock might not be synchronized.
There is no network error on the monitor, I can reach all the other machines in the cluster. The clocks are synchronized. If this problem is caused by the monmap situation how can I fix this?
Ok so as a result, directly from centos7-Nautilus to ubuntu20.04-Octopus is not possible for monitor services only, apparently the issue is about hostname resolution with different Operating systems. The rest of the services is fine. There is a longer way to do this without issue and is the correct solution. First change os from centos7 to ubuntu18.04 and install ceph-nautilus packages and add the machines to cluster (no issues at all). Then update&upgrade the system and apply "do-release-upgrade". Works like a charm. I think what eblock mentioned was this.
After installing Ubuntu v20 and then installing docker:
$ docker network create test-network
$ docker pull mongo
$ docker run --network test-network --name mongodb \
-e MONGO_INITDB_ROOT_USERNAME=admin \
-e MONGO_INITDB_ROOT_PASSWORD=pawwrord \
mongo
I got an error like this:
/usr/local/bin/docker-entrypoint.sh: line 381: 25 Illegal instruction (core dumped) "${mongodHackedArgs[#]}" --fork
Do you know what the problem is? I just need some guidance to investigate the problem.
UPDATE
I don't have any problem with other docker hub images.
Specifically only when I want to run mongo, I got this error.
MongoDB 5.0 requires a Sandy Bridge or newer CPU. Get a newer processor or use an older version of MongoDB.
https://jira.mongodb.org/browse/SERVER-54407
I have exactly same problem with yours, i try to run on my local computer work but not in VM.
thanks to this I simply changed mongo's version to 4.4 from latest which is 5.0 and running well. Maybe need newer CPU
It's a shortcoming in the available instructions of your CPU. Mongo 5.0 requires CPU instructions only available in Sandy Bridge era or more recent.
I had this problem using a Proxmox VM, which defaults to a simpler virtual CPU. Simply changing the virtual CPU to type "host" fixed the problem, by allowing the VM CPU to include all the instructions of the host CPU.
If you are running directly on metal, you'll need a newer CPU. Good luck!
I am starting with a clean install of Fedora 15 on a VirtualBox VM and trying to install Zend Server CE. To install, I adding the Zend repo to yum and ran:
sudo yum install zend-server-ce-php-5.3
The installation itself seemed to go very well. I opened the browser at http://localhost:10081/ZendServer as directed. After clicking through the license page and entering an administative password I get the error:
Failed to access Web server. Please make sure that the Web server is running and listening to the correct port
The Applications, Rules Management and Administration tabs function properly but the Monitor and Server Setup tabs both display the above error. It is a fact that the web server is not running, but when I try to rectify that I get another error:
$ sudo service httpd start
[sudo] Password for XXXXX:
Starting httpd (via systemctl): Job failed. See system logs and 'systemctl status' for details.
[FAILED]
For what it's worth (not much, I'm guessing) here are the details the message refers to:
$ sudo tail /var/log/messages
....
Jan 17 17:24:18 M5 systemd[1]: httpd.service: control process exited, code=exited status=1
Jan 17 17:24:18 M5 systemd[1]: Unit httpd.service entered failed state.
$ systemctl status httpd.service
httpd.service - LSB: start and stop Apache HTTP Server
Loaded: loaded (/etc/rc.d/init.d/httpd)
Active: failed since Tue, 17 Jan 2012 17:24:18 -0500; 3min 44s ago
Process: 19500 ExecStart=/etc/rc.d/init.d/httpd start (code=exited, status=1/FAILURE)
CGroup: name=systemd:/system/httpd.service
The diagnostics don't seem very helpful. I've tried various things, such as installing and starting httpd before installing Zend Server CE, reinstalling httpd (no good: unistalling it caused Zend to uninstall too). The httpd config isn't causing the problem as the following output demonstrates:
$ /usr/sbin/apachectl configtest
Syntax OK
Is this a know problem? What's my next move? Do I start putting debug statements in the control script to see what's failing? I can do that, but I'm hoping someone out there has dealt with this problem and can give me a quick solution.
I was able to get better information on the cause of the problem by invoking the apachectl script directly rather than using the service:
$ sudo /usr/sbin/apachectl start
httpd: Syntax error on line 220 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/zendserver_php.conf: Cannot load /usr/local/zend/lib/apache2/libphp5.so into server: /usr/local/zend/lib/apache2/libphp5.so: cannot enable executable stack as shared object requires: Permission denied
The syntax check on httpd.conf didn't catch this because it's not really a syntax error and it's not in httpd.conf either, but in the included zendserver_php.conf. A quick search shows that this error is the result of libphp5.so violating one of the constraints that SELinux enforces. SELinux is enabled by default in Fedora 15.
I don't like to reduce security, but that the only way I've seen this issue addressed. So I disabled SELinux temporarily with the command
$ sudo setenforce 0
I also edited /etc/selinux/config and changed SELINUX=enforced to SELINUX=disabled so SELinux would stay disabled on reboot. Now my web server starts without a hitch:
[mike#M5 ~]$ sudo service httpd start
Starting httpd (via systemctl): [ OK ]
I would like to think someone in the Zend development community is working on this shared library issue. Reducing security is not an acceptable work-around in a lot of cases. If anybody has a better solution, I'd still like to know it.