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#
# IMPORTANT NOTICE!!
#
# This file is no longer used and is therefore
# depricated. Priorities are now stored in the specific node.def
# files.
#
#
# Vyatta Configuration Priority File.
#
# This file controls the processing of the statements in the Vyatta
# config file when it is first read during system startup, or during
# system operation when it is read with the "load" command. It also
# applies when configuration changes are entered by users in config
# mode.
#
# It primarily affects the way in which actions are preformed at the
# time the "commit" command is issued. These actions are encoded into
# the config templates, and consist of code executed at the "update:",
# "delete:", "create", "begin:", and "end:" tags.
#
# The priority file provides a few important benefits. First, it breaks
# the configuration statements to be committed into groups whose "commit
# actions" are applied together in a "transaction".
# Second, it defines the order in which these transactions are
# performed.
#
# Breaking the config statements into multiple transactions is important
# because transactions have all-or-nothing semantics. If all the
# statements to be committed were processed in a single transaction, a
# failure of any service would mean that no services would be
# configured. Processing the statements in multiple transactions means
# that failures in one area do not necessary prevent a service in
# another area from being configured. Note that this means that the
# "commit" command executes multiple "transactions" despite what might
# be implied by the command's name.
#
# Ordering the transactions is important because some services are
# dependent on other services being configured before they are.
#
# The format of this file is as a sequence of one-line entries that have
# the following format:
#
# <priority> <config-sub-tree>
#
# The <priority> field is number in the range 0 - 1000, and is used to
# order the processing of of the config statements. The
# <config-sub-tree> field is the path to a sub-tree of the configuration
# tree.
#
# When the Vyatta config file is processed at system startup, or when a
# new config file is loaded via the "load" command, the system first
# applies each entry in the file to the proposed configuration tree via
# a "set" command. After all parameters have been set, it issues the
# "commit" command.
#
# The "commit" command reads this priority file and sorts the entries in
# increasing order by their <priority> field. We usually try to
# maintain this file sorted in increasing <priority> order so that we
# can readily see the order in which entries will be processed. Next, it
# processes each entry, starting from the lowest priority entry, and
# proceeding in increasing priority order. For each entry, it checks to
# see if the <config-sub-tree> exists in the tree of parameters to be
# committed. If it does, it takes the config statements under that
# sub-tree and removes any statements that match a deeper sub-tree that
# was processed earlier or will be processed later. If any statements
# remain, then those statements are processed together as a group in a
# "transaction".
#
# To perform the transaction, the "commit" command then iterates through
# the statements in the group, performing the commit actions associated
# with each one. If any of the commit actions fail, then the
# transaction involving this group is viewed as having failed. No
# further commit actions are performed on the remaining statements in
# the group, and the parameters that make up the group are NOT added to
# the running configuration. If no commit actions fail, then the
# transaction is viewed as having succeeded.
#
# After the "commit" command completes processing one group, it iterates
# to the next entry in the sorted priority file and repeats the process.
# If, after processing the entire priority file, any configuration
# statements remain, they are applied in one final transaction.
#
# This process has a few important consequences. First, the commit
# action for every statement in the proposed config tree is applied
# exactly once. Second, each line in this file generates at most one
# transaction. Third, a config statement may be applied in a
# transaction before one of its parent nodes is applied. Its parent may
# be a multi-node parameter. An example of this is if the routing
# protocol parameters of an interface are applied before the interface
# itself is applied. In this case, the parent nodes are created in the
# "active config" tree at the time the lower-level node is committed.
#
#
# RUN perl /opt/vyatta/sbin/priority.pl to generate the current priority listings
#
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