Commit 9340cc2b authored by Michael Hanselmann's avatar Michael Hanselmann
Browse files

vcluster: Add more details to docstrings



As requested by René Nussbaumer. Hopefully things are more clear now.
Signed-off-by: default avatarMichael Hanselmann <hansmi@google.com>
Reviewed-by: default avatarRené Nussbaumer <rn@google.com>
parent 92886204
......@@ -21,6 +21,9 @@
"""Module containing utilities for virtual clusters.
Most functions manipulate file system paths and are no-ops when the environment
variables C{GANETI_ROOTDIR} and C{GANETI_HOSTNAME} are not set. See the
functions' docstrings for details.
"""
......@@ -81,6 +84,11 @@ def _CheckHostname(hostname):
def _PreparePaths(rootdir, hostname):
"""Checks if the root directory and hostname are acceptable.
The (node-specific) root directory must have the hostname as its last
component. The parent directory then becomes the cluster-wide root directory.
This is necessary as some components must be able to predict the root path on
a remote node (e.g. copying files via scp).
@type rootdir: string
@param rootdir: Root directory (from environment)
@type hostname: string
......@@ -139,7 +147,10 @@ def ExchangeNodeRoot(node_name, filename,
_basedir=_VIRT_BASEDIR, _noderoot=_VIRT_NODEROOT):
"""Replaces the node-specific root directory in a path.
Replaces it with the root directory for another node.
Replaces it with the root directory for another node. Assuming
C{/tmp/vcluster/node1} is the root directory for C{node1}, the result will be
C{/tmp/vcluster/node3} for C{node3} (as long as a root directory is specified
in the environment).
"""
if _basedir:
......@@ -168,7 +179,9 @@ def AddNodePrefix(path, _noderoot=_VIRT_NODEROOT):
"""Adds a node-specific prefix to a path in a virtual cluster.
Returned path includes user-specified root directory if specified in
environment.
environment. As an example, the path C{/var/lib/ganeti} becomes
C{/tmp/vcluster/node1/var/lib/ganeti} if C{/tmp/vcluster/node1} is the root
directory specified in the environment.
"""
assert os.path.isabs(path)
......@@ -186,6 +199,9 @@ def AddNodePrefix(path, _noderoot=_VIRT_NODEROOT):
def _RemoveNodePrefix(path, _noderoot=_VIRT_NODEROOT):
"""Removes the node-specific prefix from a path.
This is the opposite of L{AddNodePrefix} and removes a node-local prefix
path.
"""
assert os.path.isabs(path)
......@@ -215,7 +231,7 @@ def MakeVirtualPath(path, _noderoot=_VIRT_NODEROOT):
A path is "virtualized" by stripping it of its node-specific directory and
prepending a prefix (L{_VIRT_PATH_PREFIX}). Use L{LocalizeVirtualPath} to
undo the process.
undo the process. Virtual paths are meant to be transported via RPC.
"""
assert os.path.isabs(path)
......@@ -231,6 +247,7 @@ def LocalizeVirtualPath(path, _noderoot=_VIRT_NODEROOT):
A "virtualized" path consists of a prefix (L{LocalizeVirtualPath}) and a
local path. This function adds the node-specific directory to the local path.
Virtual paths are meant to be transported via RPC.
"""
assert os.path.isabs(path)
......
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