Latest revision as of 18:09, 8 November 2024

Netavark Nftables Default

Summary

Netavark should use nftables by default to create/manage the firewall rules for the Podman containers.

Owner

Name: Paul Holzinger (luap99)
Email: <pholzing@redhat.com>
Name: Matthew Heon (mheon)
Email: <mheon@redhat.com>

Current status

Targeted release: Fedora Linux 41
Last updated: 2024-11-08
Announced
Discussion thread
FESCo issue: #3253
Tracker bug: #2304176
Release notes tracker: #121

Detailed Description

Netavark is used by Podman to configure networking for the containers. It manages interfaces and firewall rules. Currently it uses iptables by default to create the firewall rules for the containers but it can also be configured to use nftables (nft). The goal is to switch the default over to nftables. We also expect a small speed up for the container start-up times as nftables allows us to batch insert rules at once which makes it more performant and robust compared to iptables.

Feedback

Benefit to Fedora

netavark no longer requires iptables
all rules are now part of the netavark table so there are less conflicts with other tools/users who manage firewall rules
slightly faster container start-up time

Scope

Proposal owners: Paul Holzinger, Matthew Heon
- Using nftables is already supported in netavark as of version v1.10 (already included in fedora). Set a build option in the specfile to change the default driver from iptables to nftables

Other developers: N/A

Release engineering: N/A

Policies and guidelines: N/A (not needed for this Change)

Trademark approval: N/A (not needed for this Change)

Alignment with the Fedora Strategy:

Upgrade/compatibility impact

Existing containers will automatically use the new firewall driver on the next start/stop, they will not have to be recreated.

One problem that can happen is if there are running containers before the update and then it switches to use the new nftables driver it will leak the old iptables rules and not clear them up. So in this case a manually cleanup might be needed (reboot clears it as well). Given that the dnf system-upgrade requires a reboot anyway it is not something users need to worry about (except maybe on rawhide).

Early Testing (Optional)

Do you require 'QA Blueprint' support? N

How To Test

The change can be tested by setting the firewall driver to nftables in containers.conf:

$ sudo mkdir -p /etc/containers/containers.conf.d
$ echo $'[network]\nfirewall_driver="nftables"' | sudo tee /etc/containers/containers.conf.d/50-netavark-nftables.conf

Changing the firewall driver while you have running containers will likely cause some conflicting rules so it is best to reboot when this option is changed.

Now start the containers and make sure the network works as usual. The rules can be checked with

$ sudo nft list table inet netavark

Known Issue with docker

When using both rootful podman and docker together the podman containers will not have external network connectivity. This is because docker adds a iptables rule to block all forwarding. https://docs.docker.com/network/packet-filtering-firewalls/#docker-on-a-router

Users either need to add a iptables rule to allow the podman traffic or revert to iptables driver via the containers.conf file option shown under "How To Test" above.

User Experience

There should no change in behavior for end users unless they manually messed with the netavark firewall rules.

Dependencies

N/A

Contingency Plan

Contingency mechanism: Keep using iptables as default.
Contingency deadline: beta freeze
Blocks release? N/A

Documentation

N/A (not a System Wide Change)

Release Notes

@@ Line 1: / Line 1: @@
-{{admon/important | Comments and Explanations | The page source contains comments providing guidance to fill out each section. They are invisible when viewing this page. To read it, choose the "view source" link.<br/> '''Copy the source to a ''new page'' before making changes!  DO NOT EDIT THIS TEMPLATE FOR YOUR CHANGE PROPOSAL.'''}}
-{{admon/tip | Guidance | For details on how to fill out this form, see the [https://docs.fedoraproject.org/en-US/program_management/changes_guide/ documentation].}}
-{{admon/tip | Report issues | To report an issue with this template, file an issue in the [https://pagure.io/fedora-pgm/pgm_docs pgm_docs repo].}}
-<!-- The actual name of your proposed change page should look something like: Changes/Your_Change_Proposal_Name.  This keeps all change proposals in the same namespace -->
 = Netavark Nftables Default <!-- The name of your change proposal --> =
-{{Change_Proposal_Banner}}
 == Summary ==
@@ Line 16: / Line 7: @@
 Netavark should use nftables by default to create/manage the firewall rules for the Podman containers.
+== Owner ==
-== Owner ==
+* Name: [[User:luap99 | Paul Holzinger]] (luap99)
-<!--
+* Email: <pholzing@redhat.com>
-For change proposals to qualify as self-contained, owners of all affected packages need to be included here. Alternatively, a SIG can be listed as an owner if it owns all affected packages.
+* Name: [[User:mheon | Matthew Heon]] (mheon)
-This should link to your home wiki page so we know who you are.
--->
-* Name: [[User:FASAcountName| Paul Holzinger]]
-<!-- Include you email address that you can be reached should people want to contact you about helping with your change, status is requested, or technical issues need to be resolved. If the change proposal is owned by a SIG, please also add a primary contact person. -->
-* Email: <pholzing@redhat.com>, <mheon@redhat.com>
-* Name: Matthew Heon
 * Email: <mheon@redhat.com>
-<!--- UNCOMMENT only for Changes with assigned Shepherd (by FESCo)
-* FESCo shepherd: [[User:FASAccountName| Shehperd name]] <email address>
--->
 == Current status ==
-[[Category:ChangeReadyForWrangler]]
+[[Category:ChangeAcceptedF41]]
 <!-- When your change proposal page is completed and ready for review and announcement -->
 <!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler -->
@@ Line 39: / Line 21: @@
 <!-- After review, the Wrangler will move your page to Category:ChangeReadyForFesco... if it still needs more work it will move back to Category:ChangePageIncomplete-->
-<!-- Select proper category, default is Self Contained Change -->
 [[Category:SelfContainedChange]]
-<!-- [[Category:SystemWideChange]] -->
 * Targeted release: [https://docs.fedoraproject.org/en-US/releases/f41/ Fedora Linux 41]
@@ Line 51: / Line 31: @@
 ON_QA -> change is fully code complete
 -->
-* [Announced]
+* [https://lists.fedoraproject.org/archives/list/devel-announce@lists.fedoraproject.org/thread/A7ZVLT2JMLQT5YVTCFGHQVYQ5WIBFQML/ Announced]
-* [<will be assigned by the Wrangler> Discussion thread]
+* [https://discussion.fedoraproject.org/t/f41-change-proposal-netavark-nftables-default-self-contained/125528 Discussion thread]
-* FESCo issue: <will be assigned by the Wrangler>
+* FESCo issue: [https://pagure.io/fesco/issue/3253 #3253]
-* Tracker bug: <will be assigned by the Wrangler>
+* Tracker bug: [https://bugzilla.redhat.com/show_bug.cgi?id=2304176 #2304176]
-* Release notes tracker: <will be assigned by the Wrangler>
+* Release notes tracker: [https://gitlab.com/fedora/docs/fedora-linux-documentation/release-notes/-/issues/121 #121]
 == Detailed Description ==
-<!-- Expand on the summary, if appropriate.  A couple sentences suffices to explain the goal, but the more details you can provide the better. -->
 Netavark is used by Podman to configure networking for the containers. It manages interfaces and firewall rules. Currently it uses iptables by default to create the firewall rules for the containers but it can also be configured to use nftables (nft). The goal is to switch the default over to nftables. We also expect a small speed up for the container start-up times as nftables allows us to batch insert rules at once which makes it more performant and robust compared to iptables.
@@ Line 66: / Line 45: @@
 == Benefit to Fedora ==
-<!-- What is the benefit to the distribution?  Will the software we generate be improved? How will the process of creating Fedora releases be improved?
-      Be sure to include the following areas if relevant:
-      If this is a major capability update, what has changed?
-           For example: This change introduces Python 5 that runs without the Global Interpreter Lock and is fully multithreaded.
-      If this is a new functionality, what capabilities does it bring?
-           For example: This change allows package upgrades to be performed automatically and rolled-back at will.
-      Does this improve some specific package or set of packages?
-           For example: This change modifies a package to use a different language stack that reduces install size by removing dependencies.
-      Does this improve specific Spins or Editions?
-           For example: This change modifies the default install of Fedora Workstation to be more in line with the base install of Fedora Server.
-      Does this make the distribution more efficient?
-           For example: This change replaces thousands of individual %post scriptlets in packages with one script that runs at the end.
-      Is this an improvement to maintainer processes?
-           For example: Gating Fedora packages on automatic QA tests will make rawhide more stable and allow changes to be implemented more smoothly.
-      Is this an improvement targeted as specific contributors?
-           For example: Ensuring that a minimal set of tools required for contribution to Fedora are installed by default eases the onboarding of new contributors.
-     When a Change has multiple benefits, it's better to list them all.
-     Consider these Change pages from previous editions as inspiration:
-     https://fedoraproject.org/wiki/Changes/Annobin (low-level and technical, invisible to users)
-     https://fedoraproject.org/wiki/Changes/ParallelInstallableDebuginfo (low-level, but visible to advanced users)
-     https://fedoraproject.org/wiki/Changes/VirtualBox_Guest_Integration (primarily a UX change)
-     https://fedoraproject.org/wiki/Changes/NoMoreAlpha (an improvement to distro processes)
-     https://fedoraproject.org/wiki/Changes/perl5.26 (major upgrade to a popular software stack, visible to users of that stack)
--->
 * netavark no longer requires iptables
@@ Line 100: / Line 52: @@
 == Scope ==
 * Proposal owners: Paul Holzinger, Matthew Heon
-<!-- What work do the feature owners have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
 ** Using nftables is already supported in netavark as of version v1.10 (already included in fedora). Set a build option in the specfile to change the default driver from iptables to nftables
-* Other developers: <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Other developers: N/A
-<!-- What work do other developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
-* Release engineering: [https://pagure.io/releng/issues #Releng issue number] <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Release engineering: N/A
-<!-- Does this feature require coordination with release engineering (e.g. changes to installer image generation or update package delivery)?  Is a mass rebuild required?  include a link to the releng issue.
-The issue is required to be filed prior to feature submission, to ensure that someone is on board to do any process development work and testing and that all changes make it into the pipeline; a bullet point in a change is not sufficient communication -->
-* Policies and guidelines: N/A (not needed for this Change) <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Policies and guidelines: N/A (not needed for this Change)
-<!-- Do the packaging guidelines or other documents need to be updated for this feature?  If so, does it need to happen before or after the implementation is done?  If a FPC ticket exists, add a link here. Please submit a pull request with the proposed changes before submitting your Change proposal. -->
 * Trademark approval: N/A (not needed for this Change)
-<!-- If your Change may require trademark approval (for example, if it is a new Spin), file a ticket ( https://pagure.io/Fedora-Council/tickets/issues ) requesting trademark approval from the Fedora Council. This approval will be done via the Council's consensus-based process. -->
 * Alignment with the Fedora Strategy:
-<!-- Does your proposal align with the current Fedora Strategy: https://discussion.fedoraproject.org/t/fedora-strategy-2028-february-march-planning-work-and-roadmap-til-flock/43618 ? It's okay if it doesn't, but it's something to consider -->
 == Upgrade/compatibility impact ==
@@ Line 124: / Line 70: @@
 <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+Existing containers will automatically use the new firewall driver on the next start/stop, they will not have to be recreated.
+One problem that can happen is if there are running containers before the update and then it switches to use the new nftables driver it will leak the old iptables rules and not clear them up.
+So in this case a manually cleanup might be needed (reboot clears it as well). Given that the dnf system-upgrade requires a reboot anyway it is not something users need to worry about (except maybe on rawhide).
 == Early Testing (Optional) ==
-<!-- This is an optional step for system-wide changes to avail of. If you would like to build an initial proof of concept of your change and have a member of Fedora QA help you write and/or run some initial basic tests on your code, please email tests@fedoraproject.org and include the link to your change proposal. This step is *optional*. -->
-Do you require 'QA Blueprint' support? Y/N <!-- Optional Step for System-Wide Changes only -->
+Do you require 'QA Blueprint' support? N
 == How To Test ==
-<!-- This does not need to be a full-fledged document. Describe the dimensions of tests that this change implementation is expected to pass when it is done.  This can be based off of the above section if early testing has been completed. If it needs to be tested with different hardware or software configurations, indicate them.  The more specific you can be, the better the community testing can be.
-Remember that you are writing this how to for interested testers to use to check out your change implementation - documenting what you do for testing is OK, but it's much better to document what *I* can do to test your change.
-A good "how to test" should answer these four questions:
-. What special hardware / data / etc. is needed (if any)?
-. How do I prepare my system to test this change? What packages
-need to be installed, config files edited, etc.?
-. What specific actions do I perform to check that the change is
-working like it's supposed to?
-. What are the expected results of those actions?
--->
 The change can be tested by setting the firewall driver to nftables in containers.conf:
@@ Line 156: / Line 93: @@
   $ sudo nft list table inet netavark
+== Known Issue with docker ==
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+When using both rootful podman and docker together the podman containers will not have external network connectivity. This is because docker adds a iptables rule to block all forwarding.
+https://docs.docker.com/network/packet-filtering-firewalls/#docker-on-a-router
+Users either need to add a iptables rule to allow the podman traffic or revert to iptables driver via the containers.conf file option shown under "How To Test" above.
 == User Experience ==
-<!-- If this change proposal is noticeable by users, how will their experiences change as a result?
- This section partially overlaps with the Benefit to Fedora section above. This section should be primarily about the User Experience, written in a way that does not assume deep technical knowledge. More detailed technical description should be left for the Benefit to Fedora section.
- Describe what Users will see or notice, for example:
-  - Packages are compressed more efficiently, making downloads and upgrades faster by 10%.
-  - Kerberos tickets can be renewed automatically. Users will now have to authenticate less and become more productive. Credential management improvements mean a user can start their work day with a single sign on and not have to pause for reauthentication during their entire day.
- - Libreoffice is one of the most commonly installed applications on Fedora and it is now available by default to help users "hit the ground running".
- - Green has been scientifically proven to be the most relaxing color. The move to a default background color of green with green text will result in Fedora users being the most relaxed users of any operating system.
--->
 There should no change in behavior for end users unless they manually messed with the netavark firewall rules.
 == Dependencies ==
-<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this change depends?  In other words, completion of another change owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel change)? -->
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
 N/A
 == Contingency Plan ==
-<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
 * Contingency mechanism: Keep using iptables as default.
-<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
 * Contingency deadline: beta freeze
-<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
 * Blocks release? N/A
 == Documentation ==
-<!-- Is there upstream documentation on this change, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
 N/A (not a System Wide Change)

Search

Changes/NetavarkNftablesDefault: Difference between revisions