[PATCH pve-manager v4 18/20] sdn: bring up the DHCP backends at boot before the guests start

[Hannes Laimer <h.laimer@proxmox.com>]

The eBPF DHCP responder keeps its programs and maps pinned in bpffs,
so they are gone after a reboot. The SDN commit helper now brings the
DHCP backends back up on every boot, not only when it has changes to
commit.

The helper runs before the node and HA start the guests at boot.
Otherwise the first guest interface plug loads the responder with a
full pass, which holds the responder's lock exclusively. A guest
starting meanwhile waits for that lock. One that waits too long comes
up without the responder on its interface.

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
---

Notes:
    v4:
     * log that the DHCP backends are being brought up

 bin/pve-sdn-commit              | 4 ++++
 services/pve-sdn-commit.service | 1 +
 2 files changed, 5 insertions(+)

diff --git a/bin/pve-sdn-commit b/bin/pve-sdn-commit
index aa7e9b29..13231e4f 100644
--- a/bin/pve-sdn-commit
+++ b/bin/pve-sdn-commit
@@ -96,6 +96,10 @@ sub sdn_changed {
     return fabrics_changed();
 }
 
+# the dhcp backends bring back what a reboot took, pending changes or not
+print "bringing up the DHCP backends\n";
+PVE::Network::SDN::Dhcp::boot();
+
 if (!sdn_changed()) {
     print "No changes to SDN configuration detected, skipping reload\n";
     exit 0;
diff --git a/services/pve-sdn-commit.service b/services/pve-sdn-commit.service
index ff723725..825926be 100644
--- a/services/pve-sdn-commit.service
+++ b/services/pve-sdn-commit.service
@@ -3,6 +3,7 @@ Description=Commit Proxmox VE SDN changes
 DefaultDependencies=no
 Wants=pve-cluster.service network.target
 After=frr.service network.target corosync.service
+Before=pve-guests.service pve-ha-lrm.service
 
 [Service]
 ExecStart=/usr/share/pve-manager/helpers/pve-sdn-commit
-- 
2.47.3