2022-11-30 14:41:16: HTTP: No available slots... starting new Worker

I’ve installed UB server from sources in version 2.4.15 on Centos7, as a second server in network. earlier installed newest version from repo via yum, to resolve dependencies, and removed it.
I unistalled firewallD and set rules via iptables, to define which clients my new server can backup (ports taken from manual, everything looks fine).
I had to do it cause two servers in one network causing changing urbackupclientbackend.exe in windows clients somehow, and my antyvir tells users about that. so firewall, no connection - no problem.

but im seeing error from topic over and over and over again, so i assume, maybe iptables guilty for that?

But first question is, what is that worker exacly?

Why it cant start work? I’ve checked, urbackup is not starting second time (then calls about blocked ports by antoher process)

Hi, usually the error: no available slots … starting new worker is not something thats a problem. It feels more like this is the webinterface trying to talk to the backend and starting a new session with the backend as there is no active connection to send commands to at that point. If you keep getting this error, perhaps your iptables is blocking the connection to the backend? are you allowing local connections? (iptables -A INPUT -i lo -j ACCEPT for example)?

But what seems to be the exact problem? You can’t run backups to your second UrBackup server in the network? Do the clients connect to the second server? (and avoid the first?) . I’ve had issues with multiple UrBackup servers in the network, but usually resolve that by actively blocking the clients on the UrBackup servers that shouldn’t service this client through iptables rules.

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Hi, thank you for your reply, so, about local connection, yes, I have it, it was present by default, and via it wanted to do same thing as you


Thats config for my new server, for old i did opposite rules, and its blocking ip’s which should connect new server, and working with its clients - so it does work.

But new server doesn’t see its client, so I’m doing something wrong.

In the meantime i’ll try all from the begining maybe the problem is in other place

Hi Bakaczo, and what does the log say on the urbackup server (/var/log/urbackup.log) and client ? It it trying to connect but being refused? Or is it not even trying?

Not even trying, but it doesnt matter now, cause maybe urbackup isn’t a problem, but a system, so I already started doing everything from the begining, so I will let you know as soon as I finish.

Saying from the beggining i mean install new system (:

Just finished,
fresh centos, fresh newest urbackup installed via yum from uroni repo
old iptables rules, but still see any client, even when turned iptables off
BUT it is broadcasting now (info from log) but i dont see
any connection with iptraf-ng

But i see netbios-ns traffic in my LAN from multiple endpoints
urbackup.log (7.1 KB)

Now it’s working
the solution is: MORE PATIENCE : - )

Clients slowly started to show up

How Server realize that client is online? I’m asking because clients paired with buth servers shows up as offline so server won’t backup them…