It seems prudent to first mention this issue and then this aptly-named edit which seems related and has made hh_server refuse to run on NFS file systems. I am not very familar with file systems and have never touched OCaml before, so in trying to accomplish the question title, I have tried editing what I know: /etc/hh.conf and /etc/hhvm/{php, server}.ini, adding hhvm.[server.]enable_on_nfs = true by pure guesswork. No dice.
As I understand it from the issue, the change stems from the hh_server daemon being unable to register changes to the files via inotify on NFS drives, which is totally understandable. However, my VirtualBox is purely a test server for me familiarizing myself with Hack (i.e. only running the typechecker), and I've successfully run hh_client on sshfs-mounted (osxfuse) drives before. Is there another problem I'm not aware of that makes this a bad idea? If not, how might I enable hh_server --check to run on my VBox NFS shared folder?
The main issue is the lack of inotify support for NFS, so hh_server may respond with stale data.
If you accept the risk, you can add enable_on_nfs = true to /etc/hh.conf, which will enable hh_server to check folders on NFS.
Related
I'm trying to install bit vise ssh client but its not installing and throwing an exception as this.
Exception caught:
Failed to create directory "C:\Program Files(x86)\Common Files\Bitvise"
CreateDirectory() failed: windows error 5: Access is denied.
My system is 64 bit, I know bitvise has one version which supports both 64 and 32bit.
I also tried "run as Administrator", still same exception. Could anyone tell me the procedure to install it properly !
Logging: Always create an MSI log for debugging when encountering any deployment problems. See that link for hints on interpreting the log file content. Search for "value 3" first of all:
msiexec.exe /i C:\Path\Your.msi /L*vx! C:\Your.log
In general: check vendor web sites and / or user forums to figure out details on known issues. It could be a permission issue on your TEMP folder.
Emergency Approach: Use a clean virtual machine to get the software running. Try different OS-versions. Just for a heartbeat in a pinch. Or try someone else's computer. Obvious yes, but try it if you can.
Keep in mind that "very clean" virtuals (there is absolutely nothing on there - just a fresh OS) could lack certain runtimes that might be "taken for granted" and hence missing from an installer. VCRuntime, .NET versions and such. Just in case you see mysterious errors there too.
First Checks: A simplified, generic check-list for deployment issues:
AD / Group Policies: Corporate environments could have group policies and restrictions preventing the installation of anything at all. Check that first.
Installation Media: Re-download installation media to ensure its integrity.
Corrupted by Malware: Note that malware or other factors can corrupt downloaded files, but more commonly they are destroyed in-transit.
Wrong Bitness: The setup could be the wrong bitness (x64 on 32 bit system) or architecture such as Itanium (incompatible with normal x64 systems). Or even the wrong OS (zip file wrappers etc...).
Corrupted / Quarantined by Scanners: Security suites, firewalls, corporate blocks and the likes can cause problems (separate issue below - not sure if anti-virus programs try to clean binaries anymore? Block they certainly do).
Incomplete Download: Launching before download is fully finished (premature launch) is a classic weirdness - error messages are generally ok, but can be misleading. Remember to allow anti-virus scanners to complete their post-download scan. This can take much longer than you think (they hash the file, check their site, etc...).
Download Mirror Issue: Sometimes the download comes from a number of download servers, some of which could be corrupted or contain faulty media or be misconfigured. Download again - check with virustotal.com and repeat a few times to verify. Have your colleague in another office download? Different mirror likely (automatic load-balancing - when you can't pick another server yourself).
Network Problems (LAN): When you have problems, try to copy installation files to a local location (the desktop will do) to eliminate any LAN network issues as the source of your deployment problem. If there are network problems file copy might fail with a proper warning message? Network related fallacies. More towards bottom.
Missing Runtimes: A few, very core-runtimes can make setups fall over. This is particularly common on virtual machines that are "fresh" and basic.
Examples would be: VCRedist (in particular), .NET, Powershell, etc...
Lacking and more advanced components such as IIS, MSSQL, .NET Core, Java, etc... can also make some badly authored setups fall over.
Admin Rights: Ensure you have real admin rights on the box in question. In other words you are logged on using a real administrator account. Avoid "run-as" if you have a failure to look at. Try a real login.
Reboot: Just to try the obvious. Reboot and allow the PC to "settle down after reboot". This means you ensure that Windows Update hasn't started installing - or something else that was set to start pending the next reboot. PCs that are seldomly rebooted can have a lot going on after a reboot - some try to "reboot twice" - or even several times - to make sure all locks and blocks from "stuff that is happening" are released. Make sure to allow update operations to finish before rebooting once, twice or more (wait for reboot prompt). Virtual machines that are reverted to a previous state can be a nightmare when it comes to things that automatically start to update and cause confusion and problems.
Clean Slate: If you don't reboot, close down all applications before running your setup. This sorts out various locks and blocking happenstances. Preferably reboot first and run the setup the first thing you do when the machine is back up again. Again: give the machine enough time to be idle - everything started (services and such - and no updates installing).
Disk Space & Integrity: Ensure available free disk space AND that there are no errors on disk. The very small SSD and NVME disks of the last few years have made this problem more acute again.
Different user: Try installing as a different and real admin user. The important thing here is that this is a different admin account than you first tried (user account profile issues). So, in other words log in as a real admin user and don't just use "run as" (create a new account if you need to). An example of a problem could be someone who has messed up their user profile shell folder settings so that the directory table resolution of MSI fails. Another user profile would normally be unaffected and still work OK.
ACL - Access Control: Very often access denied can be related to custom NTFS ACL configuration that is erroneous. This can lead to weird error messages during installation. In corporate environments - with application packagers adapting installers - ACLs are sometimes modified extensively to tighten security. I have seen this a lot, but there are also other sources of ACL changes such as system administrator scripts, malware and I saw issues after a security fix from Windows Update a few years ago. Tightened security can trigger a lot of errors previously unseen in software that should "know better".
Malware check: Run anti-virus or Windows Defender to verify that you don't have a malware issue on your box. Additionally check the installation media with https://www.virustotal.com/ to ensure it is not malware itself! (the setup.exe could be infected, or the whole product could be malware outright - never know).
Security Software Interference: Anti-virus, firewalls, scanners and other security products can be overactive and block access to a folder or a resource so it looks like it is an ACL permission issue. Disable temporarily if possible when required. Do anti-virus software still try to fix binaries in the age of digital certificates? I am not sure. Always check installation file using virustotal.com.
Localized Setups: Sometimes setups made for other languages than English - or rather another language than the original setup (could be any language) - fail on systems with other languages installed and in use. Try on a clean virtual with the "setup-expected language". Problems like these indicate VERY bad setup design (hard coded localized paths, incorrect server paths or addresses due to translation errors, etc...) - but due to QA resources they are not uncommon. In essence the main-language version is generally (in almost all cases) put through better testing.
Mount Points: Some disks have mounted drives in folders and such things - this can cause some seriously weird problems. Try on a clean virtual with no drama-settings.
NTFS / FAT32: (Somewhat edge-case). It is no longer possible to install Windows 10 on a FAT32 drive - with the limitations that strike (no ACL permissions, max 4gb files, no journaling and such). However, the setup could be redirected to a non-system FAT32 partition or some other disk format. This could trigger security problems (no ACL permissions), but should not generally create any access denied issues - barring any custom actions trying to apply ACL permissions and failing (this might degrade gracefully by now, I don't know). However there are file size limitations in FAT32 disks (4gb) that might actually trigger errors these days for huge setups (games, video files, etc...). Note that downstream Windows OSs might still allow FAT32 system partitions. And finally - and importantly - FAT32 is not a journaling file system. This means data corruption can easily happen without self-correction.
Flagged Downloaded File: In newer versions of Windows downloaded files are flagged as "This file came from another computer and might be blocked to help protect this computer". See screenshot below. Read more details about the feature here and Digital signatures, false positives, tagged downloaded file. Just make sure your file does NOT have this flag (I do not have a complete overview of all problems that can result from this):
Odds and Ends: There are additional things such as setups being to old to install properly (they don't handle modern Windows features well - you can try to run the setup in compatibility mode by enabling this in the property page for the setup.exe file itself) and older Installshield setups had lots of DCOM-based installscript engine issues and such things. Other setup vendors have their own problems - and quite a few of them for older setups. Brand new stuff, and ancient stuff - always surprises.
Network Problems (LAN): This is mentioned above in the "Installation Media" section. You can copy files locally to try to eliminate LAN network problems as a source of problem (SAMBA problems, network overload and packet loss, interfering scanners, timeouts, etc...). You might get a real error message if you try to copy local. Try to download file directly from the Internet vendor site to the desktop as a test. Network related fallacies.
Update: Incompatibilities: It happens that software can't co-exist properly. These situations can be rather obvious (COM version incompatibilities, setups designed to detect existing software and prevent themselves from installing, setups in different language versions quarreling, etc...) or quite hard to work out (deep-seated driver problems, hardware peculiarities, anti-virus false positives or otherwise unsolvable problems). Make sure you test your setup on a clear virtual whenever you have problems. You can also use that as a "solution" if it works - have people run incompatible software on virtuals - obviously one of the key use cases for virtuals (there are many others).
Full Check List: See Section "Generic Tricks? in this answer for more.
Smartscreen issues: Digital signatures, false positives, tagged downloaded file
I'd like to upgrade to the newest version of Perl6,
rakudobrew build moar
Update git reference: rakudo
Cloning into 'rakudo'...
fatal: unable to connect to github.com:
github.com[0: 140.82.114.4]: errno=Connection timed out
Failed running git clone git://github.com/rakudo/rakudo.git rakudo at /home/con/.rakudobrew/bin/rakudobrew line 57.
main::run("git clone git://github.com/rakudo/rakudo.git rakudo") called at /home/con/.rakudobrew/bin/rakudobrew line 397
main::update_git_reference("rakudo") called at /home/con/.rakudobrew/bin/rakudobrew line 368
main::build_impl("moar", undef, "") called at /home/con/.rakudobrew/bin/rakudobrew line 115
this is just a simple connection failure, but how do I fix this?
Your connection problem is not really anything to do with any P6 related software, or in fact any software you're using. It is, as you say, "just a simple connection failure". And most such failures are transient and "fix themselves". As JJ notes, in such scenarios you just wait and then things start working again.
So by the time you read this it'll probably be working for you again without you having fixed anything. But I'm writing an answer anyway with these sections:
Consider not using rakudobrew
Connection problems that "fix themselves"
Connection problems you investigate or fix yourself
Getting around single points of failure
Consider not using rakudobrew
The main purpose of rakudobrew is to support installation of many versions of Rakudo simultaneously and the main audience for the tool is folk hacking on the Rakudo compiler, not those merely using it.
If you're just a regular user, not someone developing the Rakudo compiler and/or don't need to have multiple versions of Rakudo, with complete source code, installed simultaneously, then consider just downloading and installing Rakudo files directly, eg. via rakudo.org/files, rather than via rakudobrew.
Connection problems that "fix themselves"
rakudobrew failed because a git clone ... command failed because the connection with the github.com server timed out.
A server timing out when doing something that usually works using a connection that usually works is likely a transient problem, aka a "please try later" problem.
Transient problems typically "fix themselves" a few seconds, minutes or hours later.
If there's still a problem when you try again, and you want to spend time trying to find out what's going on officially, then look for a status page for that server.
Here are two status pages I know of for github.com:
https://www.githubstatus.com/
https://twitter.com/githubstatus?lang=en-gb.
And for unofficial scuttlebutt I suggest reading the twitter feed.
For me, right now, github.com is working fine and the status page says all systems are go.
So it should now be working for you too.
If it's not, then you can wait longer, or investigate. It you want to investigate, start by looking at the status pages above.
Connection problems you investigate or fix yourself
If github claims it's working fine then there's presumably a problem with your local internet "on-ramp" (your system or your internet service provider's) or somewhere further afield between your on-ramp and the server you're failing to connect to. (You can only know approximately where the server is based on which region of the world administers the IP address the server is associated with at any given moment.)
The next place to look will be places like the internet traffic report; this indicates traffic jams and the like across the planet. (Ignore the visual display, which is broken on some browsers, and click on the links in the table to drill down.)
If it's all green between you and the region that administers the IP address of the server you're failing to connect to, then the next place to turn would be your system's administrator and/or ISP.
Failing that, then perhaps you can ask a question at a sister stackexchange site like serverfault.com or superuser.com.
Getting around single points of failure
Perhaps you were thinking there might be some system redundancy and/or you're interested in that aspect.
P5's ecosystem and its tools are generally mature and limit spofs. This is unlike the ecosystems and tools of most of the other languages out there; so if you've gotten used to the remarkable reliability/availability of CPAN due to its avoidance of spofs, and by extension perlbrew, well, you've been spoiled by P5.
The P6 ecosystem/tool combinations are evolving in the P5 tradition.
For example, the zef package manager automatically connects to CPAN alongside github, and is built to be able to connect to other repos. The ecosystem is partway there to take advantage of this zef capability in that many modules are redundantly hosted on both CPAN and github.
rakudobrew ignores CPAN and assumes use of git repos. It is impressively configurable via its Variables.pm file which includes a %git_repos variable, which could be re-targeted to an alternative git repo site like gitlab. But no one has, to my knowledge, arranged to redundantly copy and update the relevant rakudo files to another git repo site, so this spof-avoidance ability apparently inherent in rakudobrew's code is, afaik, moot for now.
I wish to run some untrusted code using chroot.
However, many claim that chroot is not a security feature and can easily be broken out of.
Therefore my question is how does apps like https://ideone.com/ manage to run untrusted code quickly and securely. Also if chroot can be broken out of, couldn't it be possible to break out of chroot in https://ideone.com/ .
I'm not sure what untrusted code you're referring to, but chroot just changes the apparent file structure -- theoretically you can't see above a certain level. But symbolic links can still work so if your chrooted directory has a symlink to a directory above, chroot doesn't do you any good.
It's also possible for applications can get access to resources through other applications. Some clever hackers know how to exploit running apps, but if you set up the ideone environment as root, well, anything is possible.
More theoretically, you could install a master application that has full access to the file system. Then you run code in a chrooted environment. If that master app is running and listening it can relay resources to your chrooted application.
Quickly? Sure... Securely... well... with my example the master app is a gatekeeper but it's still security through trust of the master app.
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.
When using XAMPP (1.7.5 Beta) under Windows 7 (Ultimate, version 6.1, build 7600), it takes several seconds before pages actually show up. During these seconds, the browser shows "Waiting for site.localhost.com..." and Apache (httpd.exe, version 2.2.17) has 99% CPU load.
I have already tried to speed things up in several ways:
Uncommented "Win32DisableAcceptEx" in xampp\apache\conf\extra\httpd-mpm.conf
Uncommented "EnableMMAP Off" and "EnableSendfile Off" in xampp\apache\conf\httpd.conf
Disabled all firewall and antivirus software (Windows Defender/Windows Firewall, Norton AntiVirus).
In the hosts file, commented out "::1 localhost" and uncommented "127.0.0.1 localhost".
Executed (via cmd): netsh; interface; portproxy; add v6tov4 listenport=80 connectport=80.
Even disabled IPv6 completely, by following these instructions.
The only place where "HostnameLookups" is set, is in xampp\apache\conf\httpd-default.conf, to: Off.
Tried PHP in CGI mode by commenting out (in httpd-xampp.conf): LoadFile "C:/xampp/php/php5ts.dll" and LoadModule php5_module modules/php5apache2_2.dll.
None of these possible solutions had any noticeable effect on the speed. Does Apache have difficulty trying to find the destination host ('gethostbyname')? What else could I try to speed things up?
Read over Magento's Optimization White Paper, although it mentions enterprise the same methodologies will and should be applied. Magento is by no means simplistic and can be very resource intensive. Like some others mentioned I normally run within a Virtual Machine on a LAMP stack and have all my optimization's (both at server application levels and on a Magento level) preset on a base install of Magento. Running an Opcode cache like eAccelerator or APC can help improve load times. Keeping Magento's caching layers enabled can help as well but can cripple development if you forget its enabled during development, however there are lots of tools available that can clear this for you from a single command line or a tool like Alan Storms eCommerce Bug.
EDIT
Optimization Whitepaper link:
https://info2.magento.com/Optimizing_Magento_for_Peak_Performance.html
Also, with PHP7 now including OpCache, enabling it with default settings with date/time checks along with AOE_ClassPathCache can help disk I/O Performance.
If you are using an IDE with Class lookups, keeping a local copy of the code base you are working on can greatly speed up indexing in such IDEs like PHPStorm/NetBeans/etc. Atwix has a good article on Docker with Magento:
https://www.atwix.com/magento/docker-development-environment/
Some good tools for local Magento 1.x development:
https://github.com/magespecialist/mage-chrome-toolbar
https://github.com/EcomDev/EcomDev_LayoutCompiler.git
https://github.com/SchumacherFM/Magento-OpCache.git
https://github.com/netz98/n98-magerun
Use a connection profiler like Chrome's to see whether this is actually a lookup issue, or whether you are waiting for the site to return content. Since you tagged this question Magento, which is known for slowness before you optimize it, I'm guessing the latter.
Apache runs some very major sites on the internets, and they don't have several second delays, so the answer to your question about Apache is most likely no. Furthermore, DNS lookup happens between your browser and a DNS server, not the target host. Once the request is sent to the target host, you wait for a rendered response from it.
Take a look at the several questions about optimizing Magento sites on SO and you should get some ideas on how to speed your site up.