We are planning to use JProfiler to profile several live application deployed in our clients' DC.
What would be the required bandwidth to allow smooth profiling session?
The bandwidth required between the JProfiler GUI and the agent is quite low, it only requests the data that has to be displayed, not the entire profiling data.
The entire profiling data is only transmitted when you save a snapshot.
Also, is it OK to have 1 JProfiler license and have many agents installed in remote machines?
Yes, you only need a license for the JProfiler GUI, not for the profiling agent.
Related
I am very new to weblogic. Is it possible to auto-detect when the memory of the application that is hosted in weblogic goes down. Is it possible send email notification if the memory available is less than 50%? I am on weblogic 10.3.6.
I mean not by using any profiler tools, is there any feature in weblogic or any script that we can write for weblogic?
no, its not, my question mentions not by using profiling tools like VisualVM, Jconsole etc. does weblogic server has memory monitoring and alerting the admin user when memory is below certain percentage? –
So I have a cloud virtual machine on google compute, does this mean by nature that it is highly available? If the VM is running on a single piece of hardware on GCE, if the piece of hardware breaks then the VM could go down. Is the VM running on some kind of RAID, but for servers? So if one of the machines goes down another machine will pick up and continue running the vm? Thanks.
The machine itself is not highly available. However, Google takes several steps to increase reliability:
Storage is replicated and independent of the physical machine the VM is running on (obviously not for local SSD). This means that even if the physical machine catches on fire, only the "runtime" state is lost but the attached disks are fine.
VMs can live-migrate. This is a setting you can control. If enabled, the VM will be migrated to a different physical machine on maintenance events. Live-migration can lead to brief performance degradation while memory etc. is synced to the other host but the machine is not shut down / restarted.
Even when the physical host suddenly dies, you can set your instance to restart automatically on a new machine. If you plan to use this mode, make sure your instance is able to cleanly boot to serving state without manual intervention.
If you need high availability, the best approach is to spread your instances among zones of the same region and using a network or HTTP(S) loadbalancer. These will automatically stop sending traffic to a machine in case it becomes unhealthy. Also see this short youtube video on Google's network architecture for more info.
For high availability of your application data, there are highly available options like Datastore for database-like usage and Cloud Storage for file-oriented data. Keep in mind that Cloud SQL also runs on a single instance/physical machine which means that you have to setup slaves/replicas to get high availability. However, you can also do that with your favorite DB system on plain Compute Engine instances if you are willing to maintain them yourself.
I'm interested in PC firmware programming, and am just studying the UEFI spec. To my surprise, it seems like a spec for an entire OS which is embedded in firmware. You can even write UEFI "applications", which run directly using the UEFI boot services, without any other OS present.
I've found blog posts which show how to create a "Hello, world!" application which can run in the UEFI preboot environment. This is... interesting, and bizarre at the same time. I'll run my "Hello, world" programs on a regular OS, thank you.
What kind of use cases are UEFI applications actually good for? Fancy boot configuration screens? Does any "real", commercially available PC firmware use UEFI applications to implement anything more than just boot loaders and boot configuration utilities?
Anything that isn't PEI/DXE/SMM core or driver is an application, so any "real" PC have them, because BIOS Setup is actually an UEFI application. Some vendors include various other apps like firmware updaters, diagnostic and troubleshooting utilities, etc. UEFI 2.4 makes possible to add your own application with a properly filled BootXXXX/KeyXXXX variable pair and then run it by pressing a key combination during POST.
Most console applications written in C can be compiled as UEFI application by using StdLib package of current EFI Development Kit and then run in UEFI shell.
Major examples of useful UEFI apps (besides bootloaders, shell and Linux kernel, of course) are Intel ME System Tools, Read Universal, Python 2.7 and many more.
Eventually, when legacy boot will not be available anymore, all currently useful DOS utilities must either be made UEFI applications or go extinct.
Despite many valuable answers here, because I wrote couple UEFI applications myself I will try to add my 2 cents. First, what is UEFI application to just give ground what we talking about:
UEFI Specificatin v2.5:
Section 2.1.1
The major differences between image types are the memory type that the firmware
will load the image into, and the action taken when the image’s entry point exits or returns. An
application image is always unloaded when control is returned from the image’s entry point.
Section 2.1.2
When the application returns from
its entry point, or when it calls the Boot Service EFI_BOOT_SERVICES.Exit(), the application
is unloaded from memory and control is returned to the UEFI component that loaded the application.
Groups of applications that make sense in UEFI:
Configuration tools - Configuration interface for Option ROMs (ie. for storage controllers), out of band management (ie. AMT configuration tools), manufacturer performance tweaking tools
Provisioning tools - used by administrators to preload specific BIOS setting, manually setting all options in BIOS setup would be inefficient
Diagnostics tools - mostly for tests that cannot be performed in OS (DRAM tests, full storage scan, storage R/W tests, etc.). In some districts specific diagnostics tools are required in UEFI BIOS, so those can be sold to government.
Security applications - HDD encryption/decryption, antivirus scanner and anti thief applications
BIOS capability enhancement - Power Over Ethernet extensions, DRAM discovery, patching and modification of system tables (SMBIOS, ACPI)
Display tools - for displaying complex animations while running, splash screen displaying
Bootloaders - this is special type of application, which can call EFI_BOOT_SERVICES.ExitBootServices() causing termination of all memory management and passing control to Operating System.
Note that very important feature of UEFI application is that it can be added to boot order and be executed each boot time. Also UEFI application do not have to be delivered with BIOS image it can be stored in connected device memory, which is common for Option ROM configuration tools.
Here it is an example of a full blown UEFI Pre-boot Application;
There are SED SSD/HDD drives. As soon as SSD/HDD loses its power it goes into locked state (hardware-based encryption) There is no way you can get access to drive's data and all partitions on the drive are no longer even visible. Only small read-only partition (ShadowMBR) is available. UEFI firmware boots an UEFI application from that only available partition (UEFI app is written on that partition during the initialization process and when the ownership of an SED is taken). It securely authenticate user and if credentials are valid it unlocks the drive. When the drive is unlocked Shadow MBR disappears and all partitions on the drive becomes available. Then the App chain-boots the installed OS.
So if you don't have credentials you cannot even boot the OS and you cannot access the data on the drive by any means.
Here's a couple of examples:
https://github.com/NikolajSchlej/CrScreenshotDxe
UEFI DXE driver to take screenshots from GOP-compatible graphic console (yes, you can make PNG screenshots of your BIOS and save them)
http://ruexe.blogspot.com/
RU.EFI is quite an advanced tool for debugging the BIOS
Well, there are the OS loaders - both the more heavyweight ones (Windows, GRUB, BSD Loader) and the "present a menu" ones (rEFInd, Gummiboot). Shim, which enables UEFI Secure Boot for Linux platforms, consists of an application as well as installing a protocol for use by other applications.
Then you have things like the Linux kernel, which when compiled with CONFIG_EFI_STUB becomes a valid UEFI application, with the awareness of booting itself.
And firmware updates can also be shipped as UEFI applications.
The UEFI shell itself is an application.
Then there are things like factory production testing utilities, development diagnosis tools, ...
Windows 7 - 8 have UEFI installer. I'm not fully aware of the details, but I'm pretty sure this new environment gives a lot more flexibility to the developers than traditional boot environment on DVD.
Some motherboards have "instant on" features that allows you to get to a desktop screen within a few seconds. This is usually a stripped down flavor of some linux that allows you to access a web browser and play music/video. ASUS have such boards.
Docker is an abstraction of OS (kernal) and below, VM is abstraction of Hardware. What is the point of running a Docker on an VM (like Azure) (apart from app portability)? should they not be directly hosting docker on the hardware?
Docker doesn't provide effective isolation for kernel-level security exploits (there's only one ring 0, and it's shared across all containers). Thus, one could reasonably wish to have the additional isolation provided by a virtualization mechanism.
Keep in mind that much of Docker's value is not about security, but about containerization -- building and distributing portable applications in such a way as to ensure that coupling between layers occurs only where and how intended.
The advantage of a cloud system like Azure is that you can go online with your credit card and get a machine up and running in a few minutes. This is enabled by that machine being virtual. Also VMs let you share hardware across multiple users with hardware-level isolation.
If everything else was equal, i.e. you didn't need any of the features of a VM, then you would be correct that a physical machine should be used, as it will run more efficiently.
Azure and EC2 are optimized for running servers. Lots and lots of servers. Both platforms attempt to manage tons of things for you -- in Azure's case, it wants to manage even the target operating system.
However, I'd like to use such a service for a different reason: Testing.
I've got a ton of operating systems I need to support. My tests don't actually take that long, but running them on every platform is time consuming. I was going to just use a cloud service for this, thinking that these machines would be running for much less than an hour, and it wouldn't cost all that much.
The problem is that the major cloud services won't run client versions of Windows -- Windows Server only.
Is there a cloud service which would let me run every client and server version, and every service pack level, of Windows released starting with Windows 2000 SP4 to the present day?
Try CloudSigma, Defiantly can upload your own ISO's and run any x86 and 64bit OS you like on it. They have their in-house versions to get started but you can bring your own OS versions.
Based in Switzerland but they would have also the servers in the US, performance i've expected to quite good.
https://www.cloudsigma.com/
There is also a free trail on at the moment
https://cs.cloudsigma.com/accounts/signup/
The list of Open Virtualization Alliance members may have some candidates for you.
A search on the page for "operating system" suggests the following possibilities (in addition to the already-mentioned CloudSigma):
ElasticHosts
stepping stone GmbH (I'm less sure about this one)
Sublime IP
No, commercial cloud services like Azure and Amazon EC2 are themselves virtual, so you don't get a great deal of control over the operating system.
An option may be to consider renting a full physical server (colocated, or managed) and then use a battery of virtual machines to run the tests. Something like VMWare's snapshot feature sounds perfect: spin up a clean virtual machine, deploy the test code, then throw away changes to the disk once the tests have been completed.
Or, indeed, as #Stuart suggests - run the tests locally.
This definitely isn't something Azure offers - I think all of Azure's images are based near to Windows Server 2008 R2.
For EC2 you could set up images for Server 2003 through to 2008R2 - but nothing else. There are also some services out there to assist with this - e.g. VaasNet http://www.vaasnet.com/catalog
For testing the other Windows operating systems, I simply don't think there's a cloud service available to let you do this. I don't even think there are any cloud services where you can run "Virtual PC" type applications on top of the hosted operating system - as I think most of the virtualization APIs are disabled in the cloud environments (virtualization within virtualization not supported!)
Sorry to say this, but your best bet may be local test hardware running VirtualPC images.
It appears that the Xen Cloud Platform might do what you're after. This page ends with:
Guest Operating Systems: the XCP binary distribution is delivered with a wide range of Linux and Widnows guests. Check out the release notes for a complete list.
And their PDF document Xen Cloud Platform Virtual Machine Installation Guide (Release 0.1, Published October 2009) says that Windows 2000 Server has "No known issues."
(I don't have any affiliation with Xen)
In conjunction with the above, there is also a list of Xen VirtualPrivateServerProviders, several of which say they include Windows.
Buy time on an EC2 instance and use it to host VirtualBox VMs with VMs set up for each operating system you want to test for. Use a RDP client or VNC or some other means to control the guest OS. This forum post seems to point to that being possible. But yes it is not a cloud service itself and you would have todo some initial setup and configuration work yourself.