Difference between revisions of "Embedded Linux tips and tricks"
(→Setting up a Yocto prebuilt package repository for apt) |
(→Setting up a Yocto prebuilt package repository for apt) |
||
| Line 15: | Line 15: | ||
The repository used is located at http://yocto.dave.eu/imx-5.4.70-2.3.0/. The prebuilt packages were generated by Yocto Zeus, which was used to create the distro running on the target as well. | The repository used is located at http://yocto.dave.eu/imx-5.4.70-2.3.0/. The prebuilt packages were generated by Yocto Zeus, which was used to create the distro running on the target as well. | ||
| + | ===Configuring the network subsystem=== | ||
First of all, it is necessary to configure the target's network subsystem in order to access the Internet. In this example, a couple of <code>systemd</code> services are used for this purpose, namely <code>systemd-networkd</code> and <code>systemd-resolved</code>. They were configured by following these steps. | First of all, it is necessary to configure the target's network subsystem in order to access the Internet. In this example, a couple of <code>systemd</code> services are used for this purpose, namely <code>systemd-networkd</code> and <code>systemd-resolved</code>. They were configured by following these steps. | ||
| Line 74: | Line 75: | ||
Dec 15 21:34:32 orca systemd[1]: Started Network Name Resolution. | Dec 15 21:34:32 orca systemd[1]: Started Network Name Resolution. | ||
</pre> | </pre> | ||
| + | ===Configuring <code>apt</code>=== | ||
Revision as of 09:23, 14 March 2022
| HOME | SOMs | SBCs | ToloMEO Embedded Assistant |  GET A QUOTE
|
 ONLINE HELPDESK
|
| Roadmap | IoT Services | ML/AI services | Embedded Design Services |
Contents
Introduction[edit | edit source]
This page provides examples and usage notes for common tasks/issues related to typical embedded Linux systems.
How to write .wic image files to SD cards[edit | edit source]
Yocto build system can generate .wic image files. These files are usually written to SD cards to create bootable devices.
The simplest way to write such images to SD cards is to use the Balena Etcher tool, which is available for Linux, macOS, and Windows hosts. Using Etcher is straightforward, nonetheless many tutorials and examples are available on the Internet.
Advanced users can also use the well-known dd utility. This tool should be avoided unless the user knows what they are doing. If the target device is not specified properly, dd can wipe out all the data on a host's disk drive! For more details, see for instance this article.
Setting up a Yocto prebuilt package repository for apt[edit | edit source]
Occasionally, it is convenient to set up the target for installing .deb packages retrieved from a Yocto repository. The following example shows how to do that on an ORCA SOM-based target.
The repository used is located at http://yocto.dave.eu/imx-5.4.70-2.3.0/. The prebuilt packages were generated by Yocto Zeus, which was used to create the distro running on the target as well.
Configuring the network subsystem[edit | edit source]
First of all, it is necessary to configure the target's network subsystem in order to access the Internet. In this example, a couple of systemd services are used for this purpose, namely systemd-networkd and systemd-resolved. They were configured by following these steps.
Disable the Connection Manager (ConnMan) sevice to prevent conflict issues:
Create the configuration file for the network interface of interest (eth1 in the example):
Start systemd-networkd and systemd-resolved:
Both services should be active:
root@orca:~# systemctl status systemd-networkd
* systemd-networkd.service - Network Service
Loaded: loaded (/lib/systemd/system/systemd-networkd.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2021-12-15 21:34:32 UTC; 18s ago
Docs: man:systemd-networkd.service(8)
Main PID: 534 (systemd-network)
Status: "Processing requests..."
Tasks: 1
Memory: 2.0M
CGroup: /system.slice/systemd-networkd.service
`-534 /lib/systemd/systemd-networkd
Dec 15 21:34:32 orca systemd[1]: Starting Network Service...
Dec 15 21:34:32 orca systemd-networkd[534]: Enumeration completed
Dec 15 21:34:32 orca systemd[1]: Started Network Service.
Dec 15 21:34:32 orca systemd-networkd[534]: eth1: IPv6 successfully enabled
Dec 15 21:34:32 orca systemd-networkd[534]: eth0: IPv6 successfully enabled
Dec 15 21:34:36 orca systemd-networkd[534]: eth1: Gained carrier
Dec 15 21:34:38 orca systemd-networkd[534]: eth1: Gained IPv6LL
Dec 15 21:34:50 orca systemd-networkd[534]: eth1: Configured
root@orca:~# systemctl status systemd-resolved
* systemd-resolved.service - Network Name Resolution
Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2021-12-15 21:34:32 UTC; 6s ago
Docs: man:systemd-resolved.service(8)
https://www.freedesktop.org/wiki/Software/systemd/resolved
https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients
Main PID: 542 (systemd-resolve)
Status: "Processing requests..."
Tasks: 1
Memory: 1.4M
CGroup: /system.slice/systemd-resolved.service
`-542 /lib/systemd/systemd-resolved
Dec 15 21:34:32 orca systemd[1]: Starting Network Name Resolution...
Dec 15 21:34:32 orca systemd-resolved[542]: Positive Trust Anchors:
Dec 15 21:34:32 orca systemd-resolved[542]: . IN DS 19036 8 2 49aac11d7b6f6446702e54a1607371607a1a41855200fd2ce1cdde32f24e8fb5
Dec 15 21:34:32 orca systemd-resolved[542]: . IN DS 20326 8 2 e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d
Dec 15 21:34:32 orca systemd-resolved[542]: Negative trust anchors: 10.in-addr.arpa 16.172.in-addr.arpa 17.172.in-addr.arpa 18.172.in-addr.arpa 19.172.in-addr.arpa>
Dec 15 21:34:32 orca systemd-resolved[542]: Using system hostname 'orca'.
Dec 15 21:34:32 orca systemd[1]: Started Network Name Resolution.
