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Diffstat (limited to 'README')
| -rw-r--r-- | README | 91 |
1 files changed, 0 insertions, 91 deletions
@@ -254,9 +254,6 @@ more consistently across machines and developers. See the `morphlib/builder.py` file, method `setup_env` for details. -Until Baserock is properly bootstrapped, it's awkward that the `PATH` -variable gets reset. To avoid that, use the `--keep-path` option. - Hacking morph ------------- @@ -271,94 +268,6 @@ and check out the `cmdtest` utility (from <http://liw.fi/cmdtest/>). Run the checks before submitting a patch, please. -The Bootstrap Process ---------------------- - -The goal of the bootstrap process is to create an environment that has -only been built with morph. It is a long boring process that can take -a few hours. - -It can be started by running `./run-bootstrap-in-chroot $workingdir` -with some environment variables set. - -The variables are: -* `DEBIAN_MIRROR`; which must be a path suitable for passing to - debootstrap; which at the time of writing allowed http://, - file:// or ssh:// urls; **required** -* `GIT_TARBALLS`; which must be a url to a tarballs directory; - morph will try to fetch tarballs from here before trying the - git-base-url; **required** -* `snapshot`; which should be `false` (or any executable that - exits unsuccessfully) if creating a snapshot after each stage - of the bootstrap is not desirable; optional - -If snapshot is true or omitted then after each stage of the bootstrap -a tarball of the working directory is created, so that if a later stage -fails it can start from the last successful stage. - -The mirror variables allow the bootstrap to be run more quickly if the -required files are available locally. - -The mirror variables being required and snapshotting defaulting -to true are artefacts of the bootstrap process' development, where -only re-running the step that failed and using local mirrors were -essential for making fixes. - - -Bootstrap stages ----------------- - -The stages required for the bootstrap are to create a debian squeeze -chroot; build a skeleton system using the linux from scratch specified -tarballs; chroot into this system and build a system using morph with -bootstrap mode; then build the system again but instead using morph's ---staging-chroot mode and with the linux from scratch system removed. - -The squeeze chroot (stage 0) is used so that the bootstrap process does -not need to be supported on every available host system, but every host -system that can run debootstrap can be indirectly supported. - -In this stage debootstrap creates a chroot with all the packages required -to build the linux from scratch system, from then onwards every stage is -built by running baserock-bootstrap and optionally making a snapshot. - -Stage 1 builds everything in a subdirectory of the squeeze-chroot called -tree, and all the packages are built with --prefix=/tools, so the full -path for `cat` would be `$workingdir/squeeze-chroot/tree/tools/bin/cat`. - -This is done so that we have a known good system to work from, that won't -become entangled with the final system, which installed with --prefix=/usr. - -Stage 2 uses morph to build a system, while chrooted into -`$workingdir/squeeze-chroot/tree`, this naturally required PATH to include -/tools/bin. - -Morph is used to build the `foundation.morph` and `devel-bootstrap.morph` -strata in the `morphs` repository. `devel-bootstrap.morph` may not use the -same morphs as `devel.morph` because the bootstrap requires some hacks that -aren't required when a fully bootstrapped system is available. - -Morph also uses the `--bootstrap` flag to make the chunks be unpacked after -they have been built, this is required for build-dependencies to be met as -prerequisites are expected to be available on the system. - -After morph has finished a reasonably complete system should be available, -so `$workingdir/squeeze-chroot/tree/tools` is removed to save space and -make it obvious if stage 2 is missing anything needed for stage 3. - -Stage 3 builds `devel.morph` which does not need all the hacks required -in building during the bootstrap, so it should be much more like what -morph will finally build. - -Rather than using `--bootstrap`, stage 3 uses `--staging-chroot`, which -builds and extracts into a chroot, rather than using anything on the host -system. - -For this to be able to build anything `--staging-filler` is used, which -allows for specifying the environment that chunks are built in. Stage 3 -uses the strata that were build in stage 2. - - Legalese -------- |