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Langue: en

Version: 2010-06-30 (ubuntu - 24/10/10)

Section: 1 (Commandes utilisateur)


rollerd - DNSSEC-Tools daemon to manage DNSSEC key rollover


   rollerd [-options] -rrfile <rollrec_file>


The rollerd daemon manages key rollover for zones. rollerd handles both KSK and ZSK rollover, though only one rollover may take place at a time. Initiation of KSK rollovers takes precedence over the initiation of ZSK rollovers. The Pre-Publish Method of key rollover is used for ZSK key rollovers. The Double Signature Method of key rollover is used for KSK rollovers. rollerd maintains zone rollover state in files called rollrec files. The administrator may control rollerd with the rollctl command. These are described in their own sections below.

ZSK Rollover Using the Pre-Publish Method

The Pre-Publish Method has four phases that are entered when it is time to perform ZSK rollover:
     1. wait for old zone data to expire from caches
     2. sign the zone with the KSK and Published ZSK
     3. wait for old zone data to expire from caches
     4. adjust keys in keyrec and sign the zone with new Current ZSK

rollerd uses the zonesigner command during ZSK rollover phases 2 and 4. zonesigner will generate keys as required and sign the zone during these two phases.

The Pre-Publish Method of key rollover is defined in the Step-by-Step DNS Security Operator Guidance Document. See that document for more detailed information.

KSK Rollover Using the Double Signature Method

The Double Signature Method has seven phases that are entered when it is time to perform KSK rollover:
     1. wait for old zone data to expire from caches
     2. generate a new (published) KSK
     3. wait for the old DNSKEY RRset to expire from caches
     4. roll the KSKs
     5. transfer new keyset to the parent
     6. wait for parent to publish the new DS record
     7. reload the zone

rollerd uses the zonesigner command during KSK rollover phases 2 and 4. zonesigner will generate keys as required and sign the zone during these two phases.

Currently, step 6 is handled manually. In step 5, rollerd informs the administrator via email that the zone's keyset must be transferred to its parent in order for rollover to continue. In step 6, after the keyset has been transferred to the parent and the parent has published a new DS record, the administrator uses rollctl to inform rollerd that the DS record has been published and rollover may continue.

The Double Signature Method of key rollover is defined in the Step-by-Step DNS Security Operator Guidance Document. See that document for more detailed information.

KSK Rollover Using the Double Signature Method and RFC5011

RFC5011 describes how remote-validating resolvers must track KSK changes within a zone. If configured for RFC5011 behavior, rollerd and zonesigner add an extra-long period of time between the point a new KSK is created and published and the point where the actual switch to using it takes place. RFC5011 specifies that remote validators should add a ``hold-down timer'' to the rollover process, such that the new key is not added as a trust-anchor until 30 days have past. Thus, rollerd will wait for 60 days (by default) during phase 3 of the KSK rollover process if the ``istrustanchor'' field of the rollrec definition has been set to either 1 or ``yes''. To wait for a different length of time other than 60 days, use the holddowntime field.

At this time, the other conventions of RFC5011 are not being followed. Specifically, it's not waiting for a while before removing the old key and it's not adding the revoke bit to the old key after switching.

Zone Reloading

rollerd has the opportunity to inform the DNS daemon to reload a zone in KSK phase 2, KSK phase 7, ZSK phase 2, and ZSK phase 4. This is the rollerd's default behavior. However, there are situations where this shouldn't be done, such as for off-line signing.

The roll_loadzone field of the DNSSEC-Tools configuration file is a boolean field that overrides the default to force the zone-reload behavior either on or off. This field takes precedence over the default.

Similarly, the -noreload option prevents rollerd from requesting a zone reload, and it takes precedence over the roll_loadzone configuration field and the default.

rollrec Files

The zones to be managed by rollerd are described in a rollrec file. Generally speaking most people will want to use the rollinit command to create an initial rollrec file instead of typing their own from scratch. See the INITIALIZATION AND USAGE section below and the rollinit manual page for details. Each zone's entry contains data needed by rollerd and some data useful to a user. Below is a sample rollrec entry:
         roll ""
                 zonename        ""
                 zonefile        ""
                 keyrec          ""
                 directory       ""
                 kskphase        "0"
                 zskphase        "3"
                 ksk_rollsecs    "1172614842"
                 ksk_rolldate    "Tue Feb 27 22:20:42 2007"
                 zsk_rollsecs    "1172615087"
                 zsk_rolldate    "Tue Feb 27 22:24:47 2007"
                 maxttl          "60"
                 display         "1"
                 phasestart      "Tue Feb 27 22:25:07 2007"
                 # optional records for RFC5011 rolling:
                 istrustanchor   "no"
                 holddowntime    "60D"

The first line gives the rollrec entry's name. The name distinguishes it from other rollrec entries and must be unique. This may be the zone's name, but this is not a requirement. The following lines give the zone's name, the zone's signed zone file, keyrec file, the current rollover phases, the rollover timestamps, and other information.

If either of the zonefile or keyrec files do not exist, then a ``roll'' rollrec will be changed into a ``skip'' rollrec. That record will not be processed.

A more detailed explanation may be found in rollrec(5).


rollerd's execution directory is either the directory in which it is executed or the directory passed in the -directory command-line option. Any files used by rollerd that were not specified with absolute paths use this directory as their base.

A rollrec file's directory field informs rollerd where the zone's files may be found. For that zone, rollerd will move into that directory, then return to its execution directory when it finishes rollover operations for that zone. If the directory value is a relative path, it will be appended to rollerd's execution directory. If the directory value is an absolute path, it will be used as is.

Controlling rollerd with rollctl

The rollctl command is used to control the behavior of rollerd. A number of commands are available, such as starting or stopping rollover for a selected zone or all zones, turning on or off a GUI rollover display, and halting rollerd execution. The communications path between rollerd and rollctl is operating system-dependent. On Unix-like systems, it is a Unix pipe that should only be writable by the user which runs rollerd. A more detailed explanation of rollctl may be found in rollctl(8).

A Note About Files and Filenames

There are a number of files and filenames used by rollerd and zonesigner. The user must be aware of the files used by these programs, where the files are located, and where the programs are executed.

By default, rollerd will change directory to the DNSSEC-Tools directory, though this may be changed by the -directory option. Any programs started by rollerd, most importantly zonesigner, will run in this same directory. If files and directories referenced by these programs are named with relative paths, those paths must be relative to this directory.

The rollrec entry name is used as a key to the rollrec file and to the zone's keyrec file. This entry does not have to be the name of the entry's domain, but it is a very good idea to make it so. Whatever is used for this entry name, the same name must be used for the zone keyrec in that zone's keyrec file.

It is probably easiest to store rollrec files, keyrec files, zone files, and key files in a single directory.


The following steps must be taken to initialize and use rollerd. This assumes that zone files have been created, and that BIND and DNSSEC-Tools have been installed.
0. sign zones
The zones to be managed by rollerd must be signed. Use zonesigner to create the signed zone files and the keyrec files needed by rollerd. The rollrec file created in the next step must use the keyrec file names and the signed zone file names created here.
1. create rollrec file
Before rollerd may be used, a rollrec file must first be created. While this file may be built by hand, the rollinit command was written specifically to build the file.
2. select operational parameters
A number of rollerd's operational parameters are taken from the DNSSEC-Tools configuration file. However, these may be overridden by command-line options. See the OPTIONS section below for more details. If non-standard parameters are desired to always be used, the appropriate fields in the DNSSEC-Tools configuration file may be modified to use these values.
3. install the rollover configuration
The complete rollover configuration --- rollerd, rollrec file, DNSSEC-Tools configuration file values, zone files --- should be installed. The appropriate places for these locations are both installation-dependent and operating system-dependent.
4. test the rollover configuration
The complete rollover configuration should be tested.

Edit the zone files so that their zones have short TTL values. A minute TTL should be sufficient. Test rollovers of this speed should only be done in a test environment without the real signed zone.

Run the following command:

     rollerd -rrfile test.rollrec -logfile - -loglevel info -sleep 60

This command assumes the test rollrec file is test.rollrec. It writes a fair amount of log messages to the terminal, and checks its queue every 60 seconds. Follow the messages to ensure that the appropriate actions, as required by the Pre-Publish Method, are taking place.

5. set rollerd to start at boot
Once the configuration is found to work, rollerd should be set to start at system boot. The actual operations required for this step are operating system-dependent.
6. reboot and verify
The system should be rebooted and the rollerd logfile checked to ensure that rollerd is operating properly.


There are a number of operational parameters that define how rollerd works. These parameters define things such as the rollrec file, the logging level, and the log file. These parameters can be set in the DNSSEC-Tools configuration file or given as options on the rollerd command line. The command line options override values in the configuration file.

The following options are recognized:

Tells rollerd to sign the zones that aren't in the middle of being rolled. This allows rollerd to refresh signed zone signatures and allows complete management of zone signing to be taken over by rollerd.

The downside to using this option is that all the non-rolling zones will be signed after every sleep, which may be expensive computationally.

Note: The zone files are not updated or installed at this time. Manual copying and installation is still needed.

-directory dir
Sets the rollerd execution directory. This must be a valid directory.
Starts the blinkenlights graphical display program to show the status of zones managed by rollerd.
-dtconfig config_file
Name of an alternate DNSSEC-Tools configuration file to be processed. If specified, this configuration file is used in place of the normal DNSSEC-Tools configuration file not in addition to it. Also, it will be handled prior to keyrec files, rollrec files, and command-line options.
Run in the foreground and do not fork into a daemon.
-logfile log_file
Sets the rollerd log file to log_file. This must be a valid logging file, meaning that if log_file already exists, it must be a regular file. The only exceptions to this are if logfile is /dev/stdout, /dev/tty, -. Of these three, using a log_file of - is preferable since Perl will properly convert the - to the process' standard output.
-loglevel level
Sets rollerd's logging level to level. contains a list of the valid logging levels.
Prevents rollerd from telling the DNS daemon to reload zones.
Prints a set of rollerd parameters and then exits. This shows the parameters with which rollerd will execute, but very little parameter validation is performed.
-pidfile pid_file
Stores the running process PID into pid_file. This defaults to /var/run/ on most systems.
-rrfile rollrec_file
Name of the rollrec file to be processed. This is the only required ``option''.
Processes all needed steps once and exits. This is not the ideal way to run rollerd, but it is potentially useful for environments where keying material is only available when specific hardware tokens have been made available.

The timing between the steps will be potentially longer since the time between rollerd runs is dependent on when rollerd is executed. ``cmd'' lines must be added to the rollrec file to do particular actions.

The following lines should serve as examples:

   cmd "rollzsk"
   cmd "rollksk"
   cmd "dspub"   # (for when the parent publishes
                             # the new ksk)

The -singlerun option implicitly implies -foreground as well.

-sleep sleeptime
Sets rollerd's sleep time to sleeptime. The sleep time is the amount of time (in seconds) rollerd waits between processing its rollrec-based queue.
-username username
username is the user for which the rollerd daemon will be executed. The rollerd process' effective uid will be set to the uid corresponding to username.

If username is a username, it must correspond to a valid uid; if it is a uid, it must correspond to a valid username.

If rollerd does not have the appropriate O/S magic (e.g., for Unix, installed as setuid program and owned by root) then it will only be able to switch to those users to which the executing user has privilege to switch. This restriction is dependent on the operating system and the manner by which rollerd is installed.

When using this option, the target user must have access to the various directories, logs, and data files that rollerd requires to execute. Without this access, proper execution cannot occur.

Displays the version information for rollerd and the DNSSEC-Tools package.
Display a usage message.
Verbose output will be given.


rollerd uses the rndc command to communicate with the BIND named daemon. Therefore, it assumes that appropriate measures have been taken so that this communication is possible.


The following problems (or potential problems) are known:
Any process that can write to the rollover socket can send commands to rollerd. This is probably not a Good Thing.


The following potential enhancements may be made:
It'd be good to base rollerd's sleep time on when the next operation must take place, rather than a simple seconds count.
Copyright 2005-2010 SPARTA, Inc. All rights reserved. See the COPYING file included with the DNSSEC-Tools package for details.


Wayne Morrison,


blinkenlights(8), named(8), rndc(8), rollchk(8), rollctl(8), rollinit(8), zonesigner(8),,,,,


Ceux qui s'appliquent trop aux petites choses
deviennent ordinairement incapables des grandes.
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