# # 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: # # # # The field is number in the range 0 - 1000, and is used to # order the processing of of the config statements. The # 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 field. We usually try to # maintain this file sorted in increasing 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 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 #