Kernel 7.0 Upgrade Broke Every LXC Container on a Proxmox Host

The reboot that turned confidence into panic

You probably know the silence after a server reboot. The fans settle down, the login page comes back, the dashboard starts filling in, and for a few seconds you feel like the upgrade gods were feeling generous today. Then you notice the weird part: the VM boots, but every LXC container is dead. Every one of them refuses to start.

That's why this kernel 7.0 upgrade story hit a nerve. A homelab user ran the update, rebooted the Proxmox host, and suddenly all the containers were throwing errors while the virtual machine sailed through like nothing happened. The problem feels personal because containers are supposed to be the lightweight, efficient, no-fuss part of the stack. They're where people park DNS, dashboards, media tools, automation, password managers, monitoring, and all the little services that make a homelab feel alive. When they all stop at once, the whole house can feel broken.

The fix ended up being surprisingly plain: reinstall lxc-pve and pve-container, then reboot the host. That's good news, but it arrives after your stomach has already dropped through the floor. When the error first appears, it doesn't say, "Relax, a package reinstall will sort this out." It looks like the kernel jumped, the container layer tripped, and now you're standing in the rubble trying to remember which services mattered most.

LXCs live closer to the blast radius

One commenter tossed out a line that explains why this kind of failure feels so plausible: LXCs run on the host's kernel. That's the deal. A full VM brings its own guest kernel and a stronger boundary from the host's moving parts, while a container leans directly on the host kernel and the user-space plumbing around it. That's why containers are fast and efficient, and it's also why a host-level upgrade can smack them in the face.

LXCs are incredibly useful, but they do live closer to the blast radius when the host changes. A major kernel update does more than roll a number forward in the background. It can touch expectations around cgroups, namespaces, AppArmor, mount behavior, LXC binaries, Proxmox container tools, and all the stuff users don't think about until it fails. So when the VM still boots and the containers don't, you're seeing the architecture show its teeth.

One person joked that it always feels like LXCs are the ones that suffer through updates. That's a little unfair, but easy to understand. For homelab users, LXCs often become the default place to put everything small, so when they break, it feels like the entire convenience layer collapsed at once. Your VM might be fine, sure, but the dozen tiny things that make daily life smoother are now stuck behind an error message and a sinking feeling.

The logs were messy, and the advice got messy too

The troubleshooting started where it usually starts, with logs. Someone suggested checking /var/log/syslog, which immediately turned into its own mini-drama because the system didn't have that file. The user tried tail -n 50 /var/log/syslog and got "No such file or directory." Then they noticed /run/pve was missing too, which made the whole thing look less like a single container problem and more like Proxmox's runtime plumbing had gone sideways.

That's when the thread split between old habits and modern defaults. One person said they still install rsyslog everywhere because it's the first thing they look at. Another snapped back that /var/log/syslog is long gone on many setups and pushed people toward journalctl. The calmer and more useful advice was to run journalctl -b, journalctl -f, or journalctl -xef, then try starting the container again. Someone else asked for pct config 101 and pct start 101 --debug, which is exactly the kind of boring diagnostic pair that moves the ball forward.

The reported logs weren't comforting. There were monitor socket timeouts, messages about being unable to get the PID for CT 101, and a pvestatd complaint that it couldn't create a metrics temp file under /run/pve because the directory didn't exist. That last bit raises an eyebrow. When Proxmox's runtime directory is missing, containers not starting may just be the most visible symptom. It's like blaming the light switch when half the breaker panel is acting weird.

The fix was simple, which made the failure feel stranger

The final fix was almost annoyingly simple: apt install --reinstall lxc-pve pve-container, followed by a host reboot. There was no kernel rollback, no lost containers, no rebuilding the whole node from backups and no midnight migration to another machine. The user reinstalled the container packages, rebooted, and the dead LXCs came back.

A fix like that is both satisfying and unsettling. It's satisfying because the user got out clean, and unsettling because it suggests something in the upgrade path left key container components in a bad state. Maybe a package didn't install cleanly, or a post-install step didn't land. Maybe the web GUI upgrade path hid a warning the user would have seen in a terminal, or the runtime bits needed a proper refresh and didn't get one until the reinstall forced the issue. The thread doesn't prove one neat cause, but it gives admins a useful pattern: if kernel 7.0 lands and LXCs refuse to start while VMs are fine, don't immediately assume your containers are ruined.

There's a bigger lesson in there. Some of the scariest infrastructure failures turn out to be boring package-state problems. They look like deep corruption or a catastrophic bug because they happen at the bottom of your stack. A broken service is annoying, while a broken container layer feels existential. The fix can be one command, but you still have to find the calm needed to try it.

The web GUI upgrade question matters

One detail slipped in almost unnoticed: the user upgraded through the web GUI. That isn't wrong by itself. Proxmox gives users a GUI for a reason, and plenty of people prefer it. Major upgrades do have a way of making terminal purists sound less annoying, though. In a shell, you can see prompts, package conflicts, held packages, warnings, and post-install chatter in real time. A GUI can make the process feel cleaner, and sometimes cleaner means less obvious.

Nobody needs to fear the GUI, but the bigger the upgrade, the more visibility you want. The people asking how the upgrade was done were trying to work out whether something got skipped, hidden, interrupted, or left in a half-upgraded state. Kernel upgrades, Proxmox package updates, LXC userspace, container management tools, and runtime directories all need to line up. When they don't, the dashboard tells you the containers won't start, but it doesn't always tell you which layer forgot to put its shoes on.

This is where experienced admins get a little superstitious, in a useful way. They update from a console or SSH session inside tmux or screen, read the apt output, and make sure no packages are held. They check pveversion -v. They reboot on purpose instead of because the system bullied them into it, and they test one non-critical container before celebrating. None of it is glamorous, and neither is being able to sleep.

The community's three moods: troubleshoot, joke, and wince

The conversation ran in three emotional lanes. The first was practical: run debug commands, check journalctl, inspect the container config, find the actual error. That's the best side of technical communities. Someone shows up stressed, and strangers start narrowing the problem down without needing a TED Talk.

The second was cynical humor. "LXCs always suffer through updates" has the shape of a joke and the weight of experience. Another person updated after commenting, then got hit by a different networking problem inside a VM. Everything looked fine at first, then internal service authentication broke in a strange loop. A reboot fixed it, and the issue came back an hour later. That side story captures the real post-upgrade window: the system boots, but you're not done. Weirdness can wait. It can show up after services start talking to each other, after caches expire, after scheduled jobs run, or after the network stack gets enough traffic to reveal the crack.

The third mood was quiet recognition. Anyone who's run a homelab long enough knows the feeling. You update because updates are good and reboot because the kernel changed, and then something you forgot was critical stops working. Suddenly the playground has turned into infrastructure. It has users, even if the users are just you, your family, and the smart home lights that now seem weirdly judgmental.

Containers are convenient until they become the dependency graph

The sneaky thing about LXCs in Proxmox is that they multiply because they're easy. You spin up one for DNS, then one each for a reverse proxy, monitoring, download tools, a database and a dashboard, plus one for a random thing you tested six months ago and now somehow rely on. Before long, the container list stops being a list of apps and turns into a dependency graph wearing a friendly UI.

So when every LXC fails after a kernel update, the damage isn't equal across all users. For one person it might mean the media stack is down. For another, local DNS is gone and half the network feels haunted. For someone else it's authentication, automation, or backup orchestration. That's why the response to "just reinstall the packages" can be gratitude and annoyance at once. The command is simple, but the stakes around it are not.

There's also an identity thing here. Homelab users often learn by doing, and Proxmox is popular because it makes serious virtualization feel approachable. Kernel upgrades expose the professional-grade reality under the friendly surface. A hypervisor is not an app store, and containers are not little magic boxes. The host, the package state and the logs all matter. And yes, sometimes the "best approach" is to skip clicking around the GUI, drop into a shell and ask the system what actually broke.

The takeaway: don't fear kernel 7.0, but don't treat it like a theme update

This incident doesn't prove kernel 7.0 is a disaster. It doesn't even prove there's a broad LXC bug. The user fixed the issue by reinstalling Proxmox's LXC/container packages and rebooting, while others mainly offered normal diagnostic steps. Still, it's exactly the kind of post that sticks in people's heads before a major upgrade, because it was so believable.

The sane path is boring. Before upgrading, make backups and check that you can restore the containers you care about. Run the upgrade somewhere you can watch it. Use journalctl instead of chasing old syslog assumptions. After the reboot, test VMs and LXCs separately. If containers fail while VMs work, look at pct start <id> --debug, journalctl -b, package status, and whether reinstalling lxc-pve and pve-container makes sense. Don't mash buttons, don't assume all your containers are dead forever, and don't assume the GUI told you the whole story.

LXCs are powerful because they share the host, and that's also why host changes matter so much. Kernel 7.0 may be fine, Proxmox may be fine, and your containers may be one reinstall away from fine. In the moment after the reboot, though, when the VM starts and every LXC refuses, fine can feel very far away. Homelab infrastructure teaches you through small disasters, and sometimes the lesson is just one command long.