Fix flannel support on Fedora CoreOS

* Fedora CoreOS now ships systemd-udev's `default.link` while
Flannel relies on being able to pick its own MAC address for
the `flannel.1` link for tunneled traffic to reach cni0 on
the destination side, without being dropped
* This change first appeared in FCOS testing-devel 32.20200624.20.1
and is the behavior going forward in FCOS since it was added
to align FCOS network naming / configs with the rest of Fedora
and address issues related to the default being missing
* Flatcar Linux (and Container Linux) has a specific flannel.link
configuration builtin, so it was not affected
* https://github.com/coreos/fedora-coreos-tracker/issues/574#issuecomment-665487296

Note: Typhoon's recommended and default CNI provider is Calico,
unless `networking` is set to flannel directly.

CHANGES.md

@@ -8,6 +8,13 @@ Notable changes between versions.
 * Update CoreDNS from v1.6.7 to [v1.7.0](https://coredns.io/2020/06/15/coredns-1.7.0-release/)
 * Update Cilium from v1.8.1 to [v1.8.2](https://github.com/cilium/cilium/releases/tag/v1.8.2)
 
+### Fedora CoreOS
+
+* Fix support for Flannel with Fedora CoreOS ([#795](https://github.com/poseidon/typhoon/pull/795))
+  * Fedora CoreOS fixes to align network interface defaults altered MAC address assignment for
+  the `flannel.1` interface in a way that caused flannel to drop pod-to-pod traffic
+  * Configure flannel interfaces explicitly
+
 #### Addons
 
 * Update Prometheus from v2.19.2 to [v2.20.0](https://github.com/prometheus/prometheus/releases/tag/v2.20.0)

aws/fedora-coreos/kubernetes/fcc/controller.yaml

@@ -183,6 +183,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

aws/fedora-coreos/kubernetes/workers/fcc/worker.yaml

@@ -110,6 +110,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

azure/fedora-coreos/kubernetes/fcc/controller.yaml

@@ -182,6 +182,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

azure/fedora-coreos/kubernetes/workers/fcc/worker.yaml

@@ -109,6 +109,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

bare-metal/fedora-coreos/kubernetes/fcc/controller.yaml

@@ -193,6 +193,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

bare-metal/fedora-coreos/kubernetes/fcc/worker.yaml

@@ -111,6 +111,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

digital-ocean/fedora-coreos/kubernetes/fcc/controller.yaml

@@ -189,6 +189,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

digital-ocean/fedora-coreos/kubernetes/fcc/worker.yaml

@@ -114,6 +114,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

google-cloud/fedora-coreos/kubernetes/fcc/controller.yaml

@@ -182,6 +182,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |

google-cloud/fedora-coreos/kubernetes/workers/fcc/worker.yaml

@@ -109,6 +109,13 @@ storage:
         inline: |
           net.ipv4.conf.default.rp_filter=0
           net.ipv4.conf.*.rp_filter=0
+    - path: /etc/systemd/network/50-flannel.link
+      contents:
+        inline: |
+          [Match]
+          OriginalName=flannel*
+          [Link]
+          MACAddressPolicy=none
     - path: /etc/systemd/system.conf.d/accounting.conf
       contents:
         inline: |