oVirt VM running normaly but the vdisk does not exist - kvm

We have a oVirt 4.3 running in my company. We receaved a error mensagem, from a backup took, informed that snapshot could not be generated. When we saw on the host where this VM is running we can see the information about vdisk but not see it. If we looking for it not exist where should be. When we looking for the vdisk informatio on oVirt Engine the UUID is different from where it is running.
It is possible to force this "gost" to write on the storage?
I don´t know if any one has this problem before.
Best regards

Related

What is a difference between vcenter's template and virtual machine?

As in the topic.
I wonder since I cannot find this information anywhere and currently I am using a virtual machine (linux) on my vcenter which is cloned and then a special shell script is run on this freshly cloned machine to setup up environment and IP adresses etc.
Maybe I would be able to benefit from templates this way.
I think this will be helpful
https://www.robertparten.com/virtualization/vmware-difference-between-clone-and-template/
Few Differences in my opinion:-
Virtual machine is the running instance while Template is compact copy of VM ( with baseline and factory settings), which can be stored anywhere.
one need to deploy template to make running VM.
one can create copy from both VM and template but in VM you need to clone it and in case of template you need to deploy it.
moving between different setup is easy with template.
Rest are already mentioned in link provided.
But first you need to search on your own and still have doubts than only ask, that's how we all learn.
Happy Learning!
Looking at these two scenarios:
Create a template from your active VM, then deploy from the template.
Deploy from the active VM directly.
As far as I know, there will be no difference in the end result if you run these scenarios in the near future. You'll still have to run a script in order to get your IPs setup, etc.
So what's the difference?
If you mess stuff up with your active VM, change things around or whatever, you lose the ability to deploy from the (good) setup you had.
Once you make a template from your active VM, that configuration is saved as a file on the ESX (or the storage, not 100% sure) and can be re-deployed in the future.

Cannot connect to Compute Engine CentOS Virtual Machine

I am new to Virtual Machines and CLI so please bear with me.
I have a CentOS 6.5 running on Compute Engine.
I ran yum update (without creating a snapshot of the previous disk - Yes I am an idiot) and not I cannot connect to the machine using the ip address.
I tried the following steps.
Tried to connect through Filezilla - didn't work.
Tried through Putty - didn't work
Tried through the browser option given by the CE console - didn't work.
I even tried creating a snapshot and starting up another VM with the snapshot - didn't work.
If anyone knows how I can get the files and folders out from the previous disk, I can start up a new VM and transfer everything again.
I do not have the latest database and this is important.
Please help!
Thanks
Warren
The way to recover is to delete your VM without deleting the disk, then create another VM with its own boot disk, attach and mount the original disk, and recover any data that you need from it.
First things first: on the VM instances page, click on the instance name that is currently running with that disk, and uncheck the box "Delete boot disk when instance is deleted". Then delete the instance.
Now, create a new instance with its own boot disk. To differentiate this new disk from the original boot disk:
using a different OS (or version of the OS) for the new disk, e.g., if using Ubuntu, try a different version or use Debian; if using RHEL, try CentOS, or vice versa
see which one is mounted at / — this should be the new disk
Mount the original disk as read-only and recover any information you need. Once you have a backup of your data, you can remount it with read-write access and try to fix it (but back up the data first!).
I finally solved this problem thanks to Misha for sending me in the right direction.
The steps are below for anyone who has the same issue.
Problem:
While updating the Centos server using yum update, I was unable to connect back to the server.
I tried all possible combinations but no luck. This seems to be a known issue as there was some material on the Compute Engine site regarding this.
Solution:
I followed the steps as Misha suggested. I started up another VM with its own boot disk and then attached the original disk with read write access.
Note: I was unable to mount the disk as just read only.
The commands were
mkdir /mnt/sdb1
mount /dev/sdb1 /mnt/sdb1
Once I mounted the VM, I copied the files from the html folder in the sdb1 disk to the html folder in the sda1(the new boot disk).
The database was a bit more challenging.
I tried quite a few times but copying the files from /dev/sdb1/var/lib/mysql into the new disk mysql folder was not working.
I found some tutorials but nothing helped.
Finally I downloaded the files from within the /dev/sdb1/var/lib/mysql and put them in my local windows mysql installation within the data folder.
Remember you have to download everything which includes the ib_logfile0 , ib_logfile1 and ibdata1 including the folder which has the *.frm files.
Then I opened localhost/phpmyadmin and voila... the files were there.
The rest was pretty simple... Exporting and uploading the SQL scripts back to the server.
This took me about 12 hours to figure out.
Thanks again Misha.

AppEngine Backup from one app to another

I can't seem to restore my AppEngine backups to a new app as listed in the documentation.
We are using the cron backup as listed in the documentation.
I get through all the stages to launch the restore job successfully, but when it kicks of all the shards are failing with 503 errors.
I tried this with multiple backup files and the experience is the same.
any advice?
(Java runtime)
I'm posting this hoping this will help someone, as there is really lack of resources around Google's documentation and the web in general about this.
While the appengine documentation says this can be done, I actually found the piece of code that forbids this inside the data_storeadmin app.
I managed to connect through python remote-api shell, read an entity from the backup and tried saving to the datastore, but datastore.Put(entity) operation yielded: "BadRequestError: app s~app_a cannot access app s~app_b's data" so it seems to be on an even lower level.
In the end, I decided to restore only a specific namespace to the same app which was also a tedious task - but it did save the day.
I Managed to pull my backup locally through gsutil, install a python-remote-api version on my app, accessed the interactive shell and wrote this script:
https://gist.github.com/Shuky/ed8728f8eb6187475b9a
Hope this helps.
Shuky

RavenDB: How can you force RavenDB to safely release RAM?

Related to this question...
If you haven't properly configured RavenDB, it can easily exhaust your server's RAM.
Link 1
Link 2
Link 3
If you've found yourself in this predicament, how can you force RavenDB to safely release this RAM?
I thought that recycling the service would do the trick. Unfortunately this corrupted my entire RavenDB installation (fortunately in a test environment). In the Silverlight GUI, RavenDB wasn't even able to retrieve a list of the installed databases; so I wasn't able to see my documents.
Jim,
You can ask RavenDB to release memory using:
POST /admin/gc
Don't recycle the service inside of Server Manager.
Instead, issue the following command in a command prompt in your RavenDB\Server directory:
Raven.Server.exe /restart
Be patient. It might take a few minutes to restart the service.

Requested registry access is not allowed on remote box

We have developed a somewhat diffuse system for handling component installation and upgrades across server environments in an automated manner. It worked happily on our development environment, but I've run into a new problem I've not seen before when attempting to deploy it to a live environment.
The environment in question comprises ten servers, five each on two different geographical sites and domains. Each server runs a WCF based windows service that allows it to talk to each of the other servers and thus keep a track of what's installed where. To facilitate this process we make use of machine level environment variables - and modifying these obviously means registry changes.
Having got all this set up, my first attempts to use the system to install stuff seemed to work, but on one box in particular I'm getting "Requested registry access is not allowed" errors when the code tries to modify the environment variables. I've googled this, obviously, but there seem to be a variety of different causes and I'm really not sure which are the applicable ones. It doesn't help that this is a live environment and that our system has relatively limited internal logging capability.
The only clue I've got is that the guy who did the install on the development boxes wrote a very patch set of documentation on the process. This includes an instruction to modify the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\LocalAccountTokenFilterPolicy value in the registry and set it to 1. I skipped this during the installation as it looked like a rather dubious security risk. Reading the documentation about this key, it looks relevant but my initial attempts at installing stuff on other boxes without this setting enabled worked fine. Sadly the author went on extended leave over the holidays yesterday and he left no explanation of why this key was needed, so we're a bit in the dark.
Can anyone help us toward the light?
Cheers,
Matt
I've seen this error when code tries to write to the event log using something like EventLog.WriteEntry() and a source that is not a registered event source is specified. When a source is specified that has not previously been registered, it will attempt to register the source, which involves writing to the registry.
I would suggest taking a look at SysInternals Process Monitor:
http://technet.microsoft.com/en-us/sysinternals/bb896645
You can use this to monitor registry access and find out what key you're getting the access denied error on. This may give you some insight as to what is causing the problem.
Essentially he's disabling part of the Remote User Account Control. Without setting the value, Remote UAC strips administrative privileges from account tokens remotely accessing the machine. Yes, it does have security implications. See Description of User Account Control and remote restrictions in Windows Vista for an explanation.