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Diffstat (limited to 'yarns/deployment.yarn')
| -rw-r--r-- | yarns/deployment.yarn | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/yarns/deployment.yarn b/yarns/deployment.yarn index fc21b826..67aecce2 100644 --- a/yarns/deployment.yarn +++ b/yarns/deployment.yarn @@ -102,3 +102,86 @@ deployed system contains the other. Since the baserock directory is in every system, we can check for that. AND tarball test.tar contains var/lib/sysroots/test-system/baserock + +Initramfs deployments +===================== + +There's a few ways of creating an initramfs. We could: +1. Build a sysroot and: + 1. Have a chunk turn that into a cpio archive, written into /boot. + 2. Embed it in the Linux kernel image, having the initramfs as part + of the BSP. +2. Deploy an existing system as a cpio archive + 1. As a stand-alone system, without a rootfs + 2. Nested inside another system + +1.1 and 1.2 require system engineering work, so won't be mentioned here. + + SCENARIO deploying a system with an initramfs + ASSUMING there is space for 5 512M disk images + GIVEN a workspace + AND a git server + WHEN the user checks out the system branch called master + GIVEN a cluster called C in system branch master + AND a system in cluster C in branch master called S + +2.2 needs a nested system that is deployed with the initramfs write +extension. + + GIVEN a subsystem in cluster C in branch master called S.I + AND subsystem S.I in cluster C in branch master builds test-system + AND subsystem S.I in cluster C in branch master has deployment type: initramfs + +The nested system needs to be placed somewhere in the parent. The +traditional place for an initramfs is `/boot`. + + AND subsystem S.I in cluster C in branch master has deployment location: boot/initramfs.gz + +1.1 and 2.2 need the write extension to configure the boot-loader to +use the produced initramfs. Only write extensions that involve creating a disk image care, so we'll use `rawdisk.write`. + + GIVEN system S in cluster C in branch master builds test-system + AND system S in cluster C in branch master has deployment type: rawdisk + AND system S in cluster C in branch master has deployment location: test.img + AND system S in cluster C in branch master has deployment variable: DISK_SIZE=512M + +Initramfs support is triggered by the `INITRAMFS_PATH` variable. It could have been made automatic, triggering the behaviour if `/boot/initramfs.gz` exists, but: + +1. There are a bunch of possible names, some of which imply different formats. +2. If we decide on one specific name, how do we pick. +3. If we allow multiple possible names, how do we handle multiple being possible. +4. We may need to pick a non-standard name: e.g. We have a deployment + where the system loads a kernel and initramfs from a disk, then boots + the target in KVM, so the bootloader we want to use for the guest is + `initramfs.gz`, while the host's initramfs is `hyp-initramfs.gz`. +5. We may have the initramfs come from a chunk the system built, but + for speed, we want this particular deployment not to use an initramfs, + even though we have a generic image that may support one. + +For all these reasons, despite there being redundancy in some cases, +we're going to set `INITRAMFS_PATH` to the same as the nested deployment's +location. + + GIVEN system S in cluster C in branch master has deployment variable: INITRAMFS_PATH=boot/initramfs.gz + +Fully testing that the system is bootable requires a lot more time, +infrastructure and dependencies, so we're just going to build it and +inspect the result of the deployment. + + WHEN the user builds the system test-system in branch master + AND the user attempts to deploy the cluster C in branch master + THEN morph succeeded + AND file workspace/master/test/morphs/test.img exists + +If the initramfs write extension works, the rootfs image should contain +`boot/initramfs.gz`. + + WHEN disk image workspace/master/test/morphs/test.img is mounted at mnt + THEN file mnt/systems/default/run/boot/initramfs.gz exists + +If the `rawdisk` write extension worked, then the bootloader config file +will mention the initramfs, and the UUID of the disk. + + AND file mnt/extlinux.conf matches initramfs + AND file mnt/extlinux.conf matches root=UUID= + FINALLY mnt is unmounted |