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--- guide:cloud:faq [2020/08/19 17:22]
lphukungoane [FAQ]
+++ guide:cloud:faq [2021/12/09 16:42] (current)
@@ Line 9: / Line 9: @@
     *[[guide:cloud:faq|FAQs]]
-======FAQ======
+======Technical FAQs======
-**Q: Do you monitor my VM’s activity?**
+) ** Do you monitor my VM’s activity?**
-A:
+     Answer: We do not monitor user VM activity.
-**Q: I cannot SSH into my VM which was working fine yesterday, do you know what happened?**
+) ** I cannot SSH into my VM which was working fine yesterday, do you know what happened?**
-A: Please provide us more details about your VM in order to investigate. In the meantime, please click on the Instance name in the Compute -> Instances tab, and then click on the Console tab to see if there is any error output sent to the console.
+     Answer: Please provide us more details about your VM in order to investigate. In the meantime, please
+     click on the Instance name in the Compute -> Instances tab, and then click on the Console tab to see
+     if there is any error output sent to the console.
-If you see messages like below it means that the kernel has hung and you will have to hard reboot the VM using the Actions drop-down menu.
+If you see messages like below it means that the kernel has hung and you will have to hard reboot the
+VM using the Actions drop-down menu.
@@ Line 36: / Line 39: @@
-A possible way to avoid this issue in the future is described in this blog: https://www.blackmoreops.com/2014/09/22/linuxFAQ - SSH into VM Image-kernel-panic-issue-fix-hung_task_timeout_secs-blocked-120-seconds-problem/
 Basically, add these lines to "/etc/sysctl.conf":
@@ Line 54: / Line 51: @@
 A good reading describing these parameters can also be found here: https://lonesysadmin.net/2013/12/22/better-linux-disk-caching-performance-vm-dirty_ratio/
-**Q: How can I save the changes I made to my VM, so I can use it later?**
-A: You can snapshot your instance which saves its state into a new base image that you can use later. The snapshot causes the instance to be paused temporarily and it's preferable to not have disk activity while doing this, and the snapshot might even fail if the instance has (or had) a lot of data written to it since it was started. Please see the User Guide section for more info on how to take a snapshot.
+) ** How can I save the changes I made to my VM, so I can use it later?**
-**
-Q: What can I do to protect my VM by accidentally being terminated by other colleagues sharing the resources available to our project?**
+    Answer: You can snapshot your instance which saves its state into a new base image that you can use
+    later. The snapshot causes the instance to be paused temporarily and it's preferable to not have disk
+    activity while doing this, and the snapshot might even fail if the instance has (or had) a lot of data
+    written to it since it was started. Please see the User Guide section for more info on how to take a
+    snapshot.
-A: //You can “lock” the instance which will cause it to not accept any state changes, until it is “unlocked”. The operation is available in the “Actions” drop-down of each instance.
-//
-**Q: I cannot SSH into my VM which was working fine yesterday, do you know what happened my VM which was working fine yesterday, do you know what happened**?
+) ** I attached a large volume to my instance (10 TB), but when I try to format it takes a very long time. What can I do to make this step faster?**
-A: //Please provide us more details about your VM in order to investigate. In the meantime, please click on the Instance name in the Compute -> Instances tab, and then click on the Console tab to see if there is any error output sent to the console.
+Answer: We recommend you format it as XFS and use the "-K" option:
-If you see messages like below it means that the kernel has hung and you will have to hard reboot the VM using the Actions drop-down menu.//
+    mkfs.xfs -K /dev/vdb
+In our tests, it took around 3 min to format a 10 TB attached volume.
-[ 1920.399095] Not tainted 3.13.0-79-generic #123-Ubuntu
-[ 1920.399559] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
-[ 1920.400763] INFO: task apt-check:1286 blocked for more than 120 seconds.
-[ 1920.401360] Not tainted 3.13.0-79-generic #123-Ubuntu
-[ 1920.401820] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
-[ 2040.400079] INFO: task rs:main Q:Reg:1061 blocked for more than 120 seconds.
-[ 2040.400697] Not tainted 3.13.0-79-generic #123-Ubuntu
-[ 2040.401132] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
-[ 2040.401883] INFO: task apt-check:1286 blocked for more than 120 seconds.
+) ** How do I give access to another user to my instance, without giving him access to my SSH private key?**
+Answer:You should never give another user access to your credentials or private key. Please run the following commands inside your instance in order to create a new user and allow him SSH key-based access to your instance. Replace "username" with your colleague's name.
-A possible way to avoid this issue in the future is described in this blog: https://www.blackmoreops.com/2014/09/22/linux-kernel-panic-issue-fix-hung_task_timeout_secs-blocked-120-seconds-problem/
+    sudo adduser username
+    sudo usermod -a -G users username
+    mkdir /home/username/.ssh/
+    chmod 700 /home/username/.ssh/
+    chown username:username /home/username/.ssh/
+    Obtain the user’s SSH public key and add it to his home directory: /home/username/.ssh/authorized_keys
+    chown username:username /home/username/.ssh/authorized_keys
-Basically, add these lines to "/etc/sysctl.conf":
+----
-   vm.dirty_background_ratio = 5
+**For More Technical Assistance**
-   vm.dirty_ratio = 10
-And then apply them:
+If you can’t find what you are looking for, please contact our support team. We are working hard to get back to you within 1-2 business days. Submit the ticket at [[http://helpdesk.chpc.ac.za|Helpdesk]]
+----
+====== Billing FAQs======
-   sysctl -p
-A good reading describing these parameters can also be found here: https://lonesysadmin.net/2013/12/22/better-linux-disk-caching-performance-vm-dirty_ratio/
+) **I powered off my instance but I was still charged for usage!**
-**Q: How can I save the changes I made to my VM, so I can use it later?**
+     Answer: CHPC charges for resources allocated to the users whether they are actively using them or not.
+             The resources you were approved for are reserved for you therefore  you obligated to pay
+             for them.
-A: //You can snapshot your instance which saves its state into a new base image that you can use later. The snapshot causes the instance to be paused temporarily and it's preferable to not have disk activity while doing this, and the snapshot might even fail if the instance has (or had) a lot of data written to it since it was started. Please see the User Guide section for more info on how to take a snapshot.
+) **How often am I billed?**
-//
-**Q: What can I do to protect my VM by accidentally being terminated by other colleagues sharing the resources available to our project?**
+    Answer: CHPC will send out invoices on the 5th of every month for the previous calendar month usage.
-A:// You can “lock” the instance which will cause it to not accept any state changes, until it is “unlocked”. The operation is available in the “Actions” drop-down of each instance.
+) **If I have an unpaid invoice, does that unpaid invoice get rolled in to the next months invoice?**
-//
-**Q: I attached a large volume to my instance (10 TB), but when I try to format it takes a very long time. What can I do to make this step faster?**
+    Answer: Yes.
-A: //We recommend you format it as XFS and use the "-K" option://
+)** Why does my bill fluctuate each month even though I am consuming the same amount of resources each month?**
-    mkfs.xfs -K /dev/vdb
+    Answer: We charge for resources used per hour and the number of hours per month vary throughout the
+            year (28 days, 30 days, 31 days).
-//In our tests, it took around 3 min to format a 10 TB attached volume//.
+) **Why am I not receiving an invoice?**
-**Q: How do I give access to another user to my instance, without giving him access to my SSH private key?**
-A:// You should never give another user access to your credentials or private key. Please run the following commands inside your instance in order to create a new user and allow him SSH key-based access to your instance. Replace "username" with your colleague's name.//
-    sudo adduser username
-    sudo usermod -a -G users username
-    mkdir /home/username/.ssh/
-    chmod 700 /home/username/.ssh/
-    chown username:username /home/username/.ssh/
-    Obtain the user’s SSH public key and add it to his home directory: /home/username/.ssh/authorized_keys
-    chown username:username /home/username/.ssh/authorized_keys
+    Answer: CHPC sends cloud resource usage invoices to all paying users on the 5th of every month.
+If you would like to terminate your account please email  [[https://users.chpc.ac.za/helpdesk/ |helpdesk@chpc.ac.za]]
+) **I have a billing related question that is not listed here, help?**
+Answer: Email [[https://users.chpc.ac.za/helpdesk/ | helpdesk@chpc.ac.za]] with your question!

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