It happened already twice today, I try to reach the dashboard and I get "500 Internal Server Error"; I can ping the raspberry but SSH does not work (connection closed by peer)
A reboot will fix the problem
Any ideas?
There is a ton of situations here, you probably need some level of monitoring on your system. If it happens "a lot" then I'd look at a partition like your /var partition, filling up and the OS not being able to write to it.
With the reboot, typically your /tmp/ and /var partitions get cleaned out allowing you to administer the machine.
So, tl;dr? The best thing would be to set up some type of monitoring on your raspberry pi and watch the graphs. If you have no idea where to start, datadog will help you get off the ground.
Related
Been using a GCP preemptible VM for a few months without problems, but in the last 4 weeks my instances have consistently shut off anywhere from 10 minutes to 20 minutes into operation.
I'll be in the middle of training, and my notebook will suddenly disconnect. The terminal will show this error:
jupyter#fastai-instance:~$ Connection to 104.154.142.171 closed by remote host.
Connection to 104.154.142.171 closed.
ERROR: (gcloud.compute.ssh) [/usr/bin/ssh] exited with return code [255].
I then check the status of my VM, to see that it has shutdown.
I searched the terminal traceback and found this thread, which seemed promising: ERROR: (gcloud.compute.ssh) [/usr/bin/ssh] exited with return code [255]
When I ran sudo gcloud compute config-ssh my VM ran for much longer than usual before shutting down, yet shutdown in the same way after about an hour. Since then, back to the same behavior.
I know preemptible instances can be shutdown when the platform needs resources, but my understanding is that comes with some kind of warning. I've checked the status of GCP's servers after shutdowns and they appear to be fine. This is also happening the same way every time I turn my VM on, which seems too frequent for preempting.
I am not sure where to look for any clues – has anyone else had a problem like this? What's especially puzzling to me is, if it is in fact an SSH problem, why would that cause the VM itself to shutdown, rather than just break the connection?
Thanks very much for any help!
Did you try to set a shutdown script and to print something in a file for validating the state of the VM when it goes down ?
Try this as shutdown script
#!/bin/bash
curl "http://metadata.google.internal/computeMetadata/v1/instance/preempted" -H "Metadata-Flavor: Google" > /tmp/preempted.log
If there is TRUE in the file, it's because the VM has been preempted.
If a VM stops and you have an active SSH connection to that VM (via gcloud compute ssh), then it's normal that you are receiving an error. Since the VM goes down, all connections are closed, so does your SSH connection (you cannot connect to a stopped instance). The VM termination causes the SSH error, not the opposite.
When using preemptible instances, Google can reclaim the instance whenever it's needed. Note that (from the docs about preemptible instances limitations) :
Compute Engine might terminate preemptible instances at any time due to system events. The probability that Compute Engine will terminate a preemptible instance for a system event is generally low, but might vary from day to day and from zone to zone depending on current conditions.
It means that one day, your instance may be running for 24 hours without being terminated, but an other day, your instance may be stopped 30 minutes after being started if Compute Engine needs to reclaim some resources.
A comment on the "continuously shutting down" part:
(I have experienced this as well)
Keep in mind that Google prefers to shut down RECENTLY STARTED preemptible instances, over ones started earlier.
The link below (and supplied earlier) has the statement:
Generally, Compute Engine avoids preempting too many instances from a single customer and preempts new instances over older instances whenever possible.
This would generally mean that, yes, I suppose, if you are preempted, and boot up again, it is quite likely that you are going to be preempted again and again until the load in the zone reduces.
I'm surprised that Google don't simply preclude you starting the preemptible VM for a while (like 30-60 minutes?). - How much CPU is being wasted bouncing VMs up and down and crossing our fingers???
P.S. There is a dirty trick to end-around your frustration - Have 2 VMs identically configured, except for preemptibility, but only 1 underlying book disk. If you are having a bad day with preempts, simply 'move' the boot disk to the non-preemptible VM, boot it, and carry on. - It's a couple of simple gcloud commands to achieve this, easily scripted and very fast. Don't tell Google I told ya....
https://cloud.google.com/compute/docs/instances/preemptible#limitations
A compute instance I had running stopped working and I am no longer able to ssh to it from the browser. When I try it hangs forever and eventually I get the error message:
You cannot connect to the VM instance because of an unexpected error.
Wait a few moments and then try again. (#13)
I looked here for common issues. I made a snapshot and tried recreating with a larger disk, in a different region and with a bigger compute instance but I was still unable to connect. When other users try to connect they have the same problem. I'm using a standard container so I expect the google daemon should be running.
This instance was collecting tweets and writing output to GCS regularly. Since ssh stopped working the instance has also stopped writing output.
Does anyone have any idea what could have gone wrong?
I would also suggest checking the Serial Console of the machine to see if there are any messages which provide any clues. For example, if the boot disk has run out of space (which can prevent SSH connectivity), there will be some messages displayed in the Serial Console implying this.
You could also try connecting to the machine via the Serial Console to troubleshoot the issue by following the advice here.
When you try to SSH into the instance from the Cloud Shell for example, using the following command, the output should provide some clues as to why you cannot SSH into the machine:
$ gcloud compute ssh INSTANCE_NAME --zone ZONE
If you are on a VPC network, try to check the applicable network TAG that allows the instance to use SSH and provide that tag to your instance. Because it could be the Firewall rules that are blocking your instance from creating the ssh connection.
I've got a VMware ESXi server that I connected to via SSH to run a process. (I was running "vmkfstools --punchzero myVirtualDrive.vmdk" to reclaim space on a virtual disk). The SSH client connection was disconnected when the process was only 70% complete (with several hours of estimated time remaining).
Was the process terminated when the SSH client dropped its connection to the ESXi host?
Is there any way to tell if the process is still running?
I did a quick ps|grep to find it, but didn't see anything that looked like vmkfstools.
On most standard linux machines, I use "screen" to avoid SSH client disconnection issues, but since the ESXi shell is purposely a very stripped down environment, I just ran the command straight away.
Thoughts?
The command was killed when you disconnected.
What you can do to prevent this in the future is to run the command with nohup. This will run your command in the background, continuing even when your shell "hangs up".
What I usually do when I expect a command to run long:
I ssh to a Linux machine that runs 24/7
start screen
ssh to the ESXi host
start the command
This way I don't have to worry about disconnects, I can just detach screen and go home after work and reattach screen the next morning to check the status of the command.
This was exactly what I was looking for, thanks all. I attempted to unmap unused block on LUNs which is vmfs 5 file system. I run this cmd esxcli storage vmfs unmap -l [LUN-NAME] I wonder that what will happen if I close remote SSH connection while this cmd process still running.
When running "git status" or even "ls" from an apache process, I will frequently get no standard output or error, and an exit status code of -6. Other times, it just works. Any ideas why this is occurring or what it means?
If you are on a network with a lot of people, you may be running out of available concurrent connections. This assumes you are on Linux when you talk about your remote. The default of 10 concurrent secure collections is not enough if you have lots of simultaneous connections via ssh.
This is explained by git running on your local machine and then needing to access multiple files on the remote to get the picture of what is in the index and the current commit's tree.
Main OS is windows 7 64bit. Using VM player to create two vm CentOS 5.6 system. The net connection is bridge. I installed Hbase on both of the CentOS system， one is master, the other is slave. When I enter the shell, and run status 'details'.
The error from master is
zookeeper.ZKConfig: no valid quorum servers found in zoo.cfg ERROR:
org.apache.hadoop.hbase.ZooKeeperConnectionException: An error is
preventing HBase from connecting to ZooKeeper
And the error from slave is
ERROR: org.apache.hadoop.hbase.ZooKeeperConnectionException: HBase is
able to connect to ZooKeeper but the connection closes immediately.
This could be a sign that the server has too many connections (30 is
the default). Consider inspecting your ZK server logs for that error
and then make sure you are reusing HBaseConfiguration as often as you
can. See HTable's javadoc for more information.
Please give me some suggestion.
Thanks a lot
Check if this is within your .bashrc, if not, add them and restart all hbase services (do not forget to manually run them as well), that did it for me with a pseudo-distributed installation. My problem (and maybe yours as well) was that Hbase wasn't detecting it's configuration.
export HADOOP_CONF_DIR=/etc/hadoop/conf
export HBASE_CONF_DIR=/etc/hbase/conf
I see this very often on my machine. I don't have a failsafe cure, but end up running stop-all.sh, and deleting every place that hadoop and dfs (its a dfs failure) store their temp files. It seems to happen after my computer goes to sleep while dfs is running.
I am going to experiment with single-user mode to avoid this. I dont need distribution while developing.