README
¶
zrepl
zrepl is a one-stop ZFS backup & replication solution.
User Documentation
User Documentation can be found at zrepl.github.io.
Bug Reports
- If the issue is reproducible, enable debug logging, reproduce and capture the log.
- Open an issue on GitHub, with logs pasted as GitHub gists / inline.
Feature Requests
- Does your feature request require default values / some kind of configuration? If so, think of an expressive configuration example.
- Think of at least one use case that generalizes from your concrete application.
- Open an issue on GitHub with example conf & use case attached.
- Optional: Post a bounty on the issue, or contact Christian Schwarz for contract work.
The above does not apply if you already implemented everything. Check out the Coding Workflow section below for details.
Building, Releasing, Downstream-Packaging
This section provides an overview of the zrepl build & release process.
Check out docs/installation/compile-from-source.rst for build-from-source instructions.
Overview
zrepl is written in Go and uses Go modules to manage dependencies. The documentation is written in ReStructured Text using the Sphinx framework.
Install build dependencies using ./lazy.sh devsetup.
lazy.sh uses python3-pip to fetch the build dependencies for the docs - you might want to use a venv.
If you just want to install the Go dependencies, run ./lazy.sh godep.
The test suite is split into pure Go tests (make test-go) and platform tests that interact with ZFS and thus generally require root privileges (sudo make test-platform).
Platform tests run on their own pool with the name zreplplatformtest, which is created using the file vdev in /tmp.
For a full code coverage profile, run make test-go COVER=1 && sudo make test-platform && make cover-merge.
An HTML report can be generated using make cover-html.
Code generation is triggered by make generate. Generated code is committed to the source tree.
Build & Release Process
The Makefile is catering to the needs of developers & CI, not distro packagers.
It provides phony targets for
- local development (building, running tests, etc)
- building a release in Docker (used by the CI & release management)
- building .deb and .rpm packages out of the release artifacts.
Build tooling & dependencies are documented as code in lazy.sh.
Go dependencies are then fetched by the go command and pip dependencies are pinned through a requirements.txt.
We use CircleCI for continuous integration. There are two workflows:
-
ciruns for every commit / branch / tag pushed to GitHub. It is supposed to run very fast (<5min and provides quick feedback to developers). It runs formatting checks, lints and tests on the most important OSes / architectures. Artifacts are published to minio.cschwarz.com (see GitHub Commit Status). -
releaseruns- on manual triggers through the CircleCI API (in order to produce a release)
- periodically on
masterArtifacts are published to minio.cschwarz.com (see GitHub Commit Status).
Releases are issued via Git tags + GitHub Releases feature. The procedure to issue a release is as follows:
- Issue the source release:
- Git tag the release on the
masterbranch. - Push the tag.
- Run
./docs/publish.shto re-build & push zrepl.github.io.
- Git tag the release on the
- Issue the official binary release:
- Run the
releasepipeline (triggered via CircleCI API) - Download the artifacts to the release manager's machine.
- Create a GitHub release, edit the changelog, upload all the release artifacts, including .rpm and .deb files.
- Issue the GitHub release.
- Add the .rpm and .deb files to the official zrepl repos, publish those.
- Run the
Official binary releases are not re-built when Go receives an update. If the Go update is critical to zrepl (e.g. a Go security update that affects zrepl), we'd issue a new source release.
The rationale for this is that whereas distros provide a mechanism for this ($zrepl_source_release-$distro_package_revision), GitHub Releases doesn't which means we'd need to update the existing GitHub release's assets, which nobody would notice (no RSS feed updates, etc.).
Downstream packagers can read the changelog to determine whether they want to push that minor release into their distro or simply skip it.
Additional Notes to Distro Package Maintainers
- Run the platform tests (Docs -> Usage -> Platform Tests) on a test system to validate that zrepl's abstractions on top of ZFS work with the system ZFS.
- Ship a default config that adheres to your distro's
hierand logging system. - Ship a service manager file and please try to upstream it to this repository.
dist/systemdcontains a Systemd unit template.
- Ship other material provided in
./dist, e.g. in/usr/share/zrepl/. - Have a look at the
Makefile'sZREPL_VERSIONvariable and how it passed to Go'sldFlags. This is howzrepl versionknows what version number to show. Your build system should set theldFlagsflags appropriately and add a prefix or suffix that indicates that the given zrepl binary is a distro build, not an official one. - Make sure you are informed about new zrepl versions, e.g. by subscribing to GitHub's release RSS feed.
Contributing Code
- Open an issue when starting to hack on a new feature
- Commits should reference the issue they are related to
- Docs improvements not documenting new features do not require an issue.
Breaking Changes
Backward-incompatible changes must be documented in the git commit message and are listed in docs/changelog.rst.
Glossary & Naming Inconsistencies
In ZFS, dataset refers to the objects filesystem, ZVOL and snapshot.
However, we need a word for filesystem & ZVOL but not a snapshot, bookmark, etc.
Toward the user, the following terminology is used:
- filesystem: a ZFS filesystem or a ZVOL
- filesystem version: a ZFS snapshot or a bookmark
Sadly, the zrepl implementation is inconsistent in its use of these words: variables and types are often named dataset when they in fact refer to a filesystem.
There will not be a big refactoring (an attempt was made, but it's destroying too much history without much gain).
However, new contributions & patches should fix naming without further notice in the commit message.
Documentation
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
|
hooks
Package hooks implements pre- and post snapshot hooks.
|
Package hooks implements pre- and post snapshot hooks. |
|
logging/trace
package trace provides activity tracing via ctx through Tasks and Spans
|
package trace provides activity tracing via ctx through Tasks and Spans |
|
Package endpoint implements replication endpoints for use with package replication.
|
Package endpoint implements replication endpoints for use with package replication. |
|
Package replication implements replication of filesystems with existing versions (snapshots) from a sender to a receiver.
|
Package replication implements replication of filesystems with existing versions (snapshots) from a sender to a receiver. |
|
Package rpc implements zrepl daemon-to-daemon RPC protocol on top of a transport provided by package transport.
|
Package rpc implements zrepl daemon-to-daemon RPC protocol on top of a transport provided by package transport. |
|
dataconn/heartbeatconn/integration_test_variablereceiverate
This integration test exercises the behavior of heartbeatconn where the server is slow at handling the data received over the connection.
|
This integration test exercises the behavior of heartbeatconn where the server is slow at handling the data received over the connection. |
|
dataconn/microbenchmark
microbenchmark to manually test rpc/dataconn performance
|
microbenchmark to manually test rpc/dataconn performance |
|
dataconn/timeoutconn
package timeoutconn wraps a Wire to provide idle timeouts based on Set{Read,Write}Deadline.
|
package timeoutconn wraps a Wire to provide idle timeouts based on Set{Read,Write}Deadline. |
|
dataconn/timeoutconn/internal/wireevaluator
a tool to test whether a given transport implements the timeoutconn.Wire interface
|
a tool to test whether a given transport implements the timeoutconn.Wire interface |
|
grpcclientidentity
Package grpcclientidentity makes the client identity provided by github.com/zrepl/zrepl/daemon/transport/serve.{AuthenticatedListener,AuthConn} available to gRPC service handlers.
|
Package grpcclientidentity makes the client identity provided by github.com/zrepl/zrepl/daemon/transport/serve.{AuthenticatedListener,AuthConn} available to gRPC service handlers. |
|
grpcclientidentity/example
This package demonstrates how the grpcclientidentity package can be used to set up a gRPC greeter service.
|
This package demonstrates how the grpcclientidentity package can be used to set up a gRPC greeter service. |
|
grpcclientidentity/grpchelper
Package grpchelper wraps the adaptors implemented by package grpcclientidentity into a less flexible API which, however, ensures that the individual adaptor primitive's expectations are met and hence do not panic.
|
Package grpchelper wraps the adaptors implemented by package grpcclientidentity into a less flexible API which, however, ensures that the individual adaptor primitive's expectations are met and hence do not panic. |
|
netadaptor
Package netadaptor implements an adaptor from transport.AuthenticatedListener to net.Listener.
|
Package netadaptor implements an adaptor from transport.AuthenticatedListener to net.Listener. |
|
transportmux
Package transportmux wraps a transport.{Connecter,AuthenticatedListener} to distinguish different connection types based on a label sent from client to server on connection establishment.
|
Package transportmux wraps a transport.{Connecter,AuthenticatedListener} to distinguish different connection types based on a label sent from client to server on connection establishment. |
|
versionhandshake
Package versionhandshake wraps a transport.{Connecter,AuthenticatedListener} to add an exchange of protocol version information on connection establishment.
|
Package versionhandshake wraps a transport.{Connecter,AuthenticatedListener} to add an exchange of protocol version information on connection establishment. |
|
Package transport defines a common interface for network connections that have an associated client identity.
|
Package transport defines a common interface for network connections that have an associated client identity. |
|
fromconfig
Package fromconfig instantiates transports based on zrepl config structures (see package config).
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Package fromconfig instantiates transports based on zrepl config structures (see package config). |
|
util
|
|
|
chainlock
package chainlock implements a mutex whose Lock and Unlock methods return the lock itself, to enable chaining.
|
package chainlock implements a mutex whose Lock and Unlock methods return the lock itself, to enable chaining. |
|
choices
Package choice implements a flag.Value type that accepts a set of choices.
|
Package choice implements a flag.Value type that accepts a set of choices. |
|
devnoop
package devnoop provides an io.ReadWriteCloser that never errors and always reports reads / writes to / from buffers as complete.
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package devnoop provides an io.ReadWriteCloser that never errors and always reports reads / writes to / from buffers as complete. |
|
nodefault
Package nodefault provides newtypes around builtin Go types so that if the newtype is used as a field in a struct and that field is zero-initialized (https://golang.org/ref/spec#The_zero_value), accessing the field will cause a null pointer deref panic.
|
Package nodefault provides newtypes around builtin Go types so that if the newtype is used as a field in a struct and that field is zero-initialized (https://golang.org/ref/spec#The_zero_value), accessing the field will cause a null pointer deref panic. |
|
zfscmd
Package zfscmd provides a wrapper around packate os/exec.
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Package zfscmd provides a wrapper around packate os/exec. |