We've had an issue today with the nginx resolver in an AWS environment. According to the nginx log files, nginx did not resolve to the right servers, after the DNS record changes.  The DNS originally resolved:  webservers.ourservers.local A 10.0.0.5 webservers.ourservers.local A 10.0.1.8   ... but as soon as one of these IP addresses changed, nginx did not get the change - and continuously tried to reach the outdated ip address - far longer than the 60 seconds ttl.  According to nginx.org/en/docs/http/ngx_http_core_module.html#resolver, the nginx resolver caches answers for the ttl only - or, in our case, for the configured time.  My colleagues moved the resolver line from the location block to the server block, - but it did not help. We need to restart nginx in order to force it to resolve to the new ip.  Nginx configuration:  http {     include       /etc/nginx/mime.types;     default_type  application/octet-stream;      log_format  main  '$scheme - $http_x_client_ip - $remote_addr - $remote_user [$time_local] "$request" '                       '$status $body_bytes_sent "$http_referer" '                       '"$http_user_agent" "$http_x_forwarded_for"';      access_log  /var/log/nginx/access.log  main;     error_log   /var/log/nginx/error.log;      server {         listen 8080 default;          set $OUR_ROOT /var/www/pub;          location /health_check.html {             root $OUR_ROOT;             auth_basic off;             allow all;         }          location / {             # Work around to flush Nginx: http://nginx.org/en/docs/http/ngx_http_core_module.html#resolver             # https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_DHCP_Options.html#AmazonDNS             # This is will be your VPC's IPv4 CIDR value + 2             # You can find this value in /etc/resolv.conf on the EC2 instance             resolver 10.0.0.2 valid=15s;              proxy_pass http://webservers.ourservers.local; # Will be resolved by Route 53             proxy_set_header X-Real-IP  $remote_addr;             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;             proxy_set_header X-Forwarded-Proto https;             proxy_set_header X-Forwarded-Proto-New https;             proxy_set_header X-Forwarded-Port 443;             proxy_set_header Host $host;             proxy_redirect     off;         }     }      #include custom config     include /etc/nginx/conf.d/*.conf; }   We use nginx version 1.13.7.  What did we do wrong? How can we make nginx re-fetch the dns records?    Update/Clarification:  10.0.0.2 is the AWS internal nameserver for VPCs:  . It does resolve correctly when checked via dig, even when nginx does not resolve correctly at the same time: We have tested these cases with   dig webservers.ourservers.local @10.0.0.2
I am using nginx/0.7.68, running on CentOS, with the following configuration:  server {     listen       80;     server_name ***;     index index.html index.htm index.php default.html default.htm default.php;      location / {             root   /***;             proxy_pass   http://***:8888;             index  index.html index.htm;     }     # where *** is my variables   The proxy_pass is to a DNS record whose IP changes frequently. Nginx caches the outdated IP address, resulting in a request to the wrong IP address.  How can I stop nginx from caching the IP address, when it is outdated?
Windows 7 File Explorer search not working Intuitive meaning of Globally Hyperbolic I am been studying differential geometry and spacetime and I keep coming across the term . I am having a hard time coming up with an intuitive understanding of this idea. What is an intuitive meaning of globally hyperbolic.  My background is mostly mathematics at a higher undergraduate level. If a linear operator has an adjoint operator, it is bounded l, ls & la -- what are the differences, and are there more of these commands? Specifing ip address for outbound connections on a multi ip host one of my servers (Debian 5.0.6) has two public ip-address on the same interface. This used to work well for months but suddenly it is using "the wrong" ip addresses for outgoing connections. This is a problem because the reverse lookup will not match and emails therefore get spam points.  eth0      Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:81.169.180.51  Bcast:81.169.180.51  Maske:255.255.255.255           inet6-Adresse: fe80::21b:21ff:fe14:8e9c/64 Gültigkeitsbereich:Verbindung  eth0:0    Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:85.214.157.120  Bcast:85.214.157.120  Maske:255.255.255.255   Kernel-IP-Routentabelle Destination     Router          Genmask         Flags Metric Ref    Use Iface 81.169.180.1    0.0.0.0         255.255.255.255 UH    0      0        0 eth0 0.0.0.0         81.169.180.1    0.0.0.0         UG    0      0        0 eth0   Currently it is using 85.214.157.120 for outbound connections. How do I get it to use 81.169.180.51?  Edit: The netmask of 255.255.255.255 is consistent with both documentation and DHCP response of the hosting company. Calling /etc/init.d/networking restart multiple times will eventually end up with the correct ip-address for outbount connections. But that is obviously not a stable solution. /Edit  Edit 2: To make sure that the host route is not related to my issue, I setup a local test network:  eth0      inet Adresse:192.168.0.2  Bcast:192.168.0.255  Maske:255.255.255.0 eth0:0    inet Adresse:192.168.0.3  Bcast:192.168.0.255  Maske:255.255.255.0  192.168.0.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0 0.0.0.0        192.168.0.1     0.0.0.0         UG    0      0        0 eth0   If anyone has an idea how to make sure that source ip-address 192.168.0.2 is used on outbound tcp connections, I'd be thankful. /Edit 2 How will Ubuntu automatically allocate the disk partition sizes when we select Erase disk and install Ubuntu during installation?    Can the settings for automatic space allocation be changed? What is sudo apt-get -f install? what is the usage of apt-get -f install . when I run sudo apt-get update I got some errors at the end It says try apt-get -f install. What is this command?  the last part of my error is :   . . .   going to be installed   E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). Moving users folder on Windows Vista/7 to another partition When I format the computer and reinstall Windows, my first step is move the My Documents folder to another partition. In Windows XP it wasn't enough because the desktop folder and another user folders was in the primary partition.  Now in Windows Vista and 7 we can use junctions/symlinks to "move" the folder to another partition and Windows and another programs will think that the data is in the primary partition.  What the fastest and secure steps to move the Users folder to another partition and to create the hardlinks correctly? If anonymity is so important, why is it not universal? A frequent argument brought up in support of voting anonymity is that it can lead to potential grudges. Certainly the review system is of the same nature.  I cannot wrap my mind around the fact that voting is anonymous and reviewing is not. Either both should be public--and this would be fine since public reviewing has been successful--or both should be anonymous--and I assume this would be the desired option since this community holds anonymity so dear.  One could say that voting rates the posts, the actual meat of the site, while reviewing is based on clarifying the purpose of the site and cleaning it up.   answer makes the point that the community can trust that votes are a good measure of quality for the very reason that they do not know who cast them; the mentality that a high-ranking member may have supported something could blur the line between "science" and "politics/religion."  Reviewing, then, can be seen as a judgment of specific members rather than quality of edit/questions, which seems to fall precisely under the "politics/religion" umbrella--the review system is much more vulnerable to grudges due to this.  So let's discuss the differences and the implications of these disjointed anonymity policies. Is it possible for information to be transmitted faster than light by using a rigid pole? gdal_translate- why jpg compressed tif is 2 times greater than jpg file? In Java Edition, I can name a mob by using NBT tags like this: /summon zombie ~ ~ ~ {CustomName:'{&quot;text&quot;:&quot;TheUndead&quot;}'}  But in Bedrock Edition, I've heard NBT is not accessible from commands. What can I do to summon a mob with a custom name tag using the /summon command? Did other meta-humans enter a coma? In the first episode of The Flash (2014), Barry's struck by lightning, some chemicals fall on him, and he enters a coma for 9 months.  This happens when the S.T.A.R. Labs particle accelerator is turned on for the first time.  9 months later, he wakes up and has powers.  He then starts fighting crime, especially other meta-humans who were created by the same particle accelerator accident.  However, this is all 9 months after the accident, where were the other meta-humans during those 9 months?  The S.T.A.R. Labs people make it sound like they hadn't seen any meta-humans active during the 9 months Barry was out.  Did all people granted powers by the particle accelerator accident also fall into comas?  Why weren't they active heroes/villains during the 9 month gap? How do I take a screenshot on my Mac? What's the easiest way to take a screenshot of my Mac?  I've used Grab.app, but it's a bit annoying just to get a quick screenshot. Is there a faster way? How to change horizontal alignment of \frac? Typing \frac{W+W^*}{2} gives a fraction in which the denominator appears to the eye to be in the wrong position. Is there a way to correct this, i.e. place the 2 in under the + (without using arbitrary negative spacing)? I need to have one column as the primary key and another to auto increment an order number field. Is this possible?  EDIT: I think I'll just use a composite number as the order number. Thanks anyways. Can I read and write to the same file in Linux without overwriting it? Error message on Terminal launch mysterious error: \pdfendlink ended up in different nesting level than \pdfstartlink I ran into the "mysterious"  \pdfendlink ended up in different nesting level than \pdfstartlink   error.  According to , "this happens when hyperref is used under pdftex and a citation splits across a page boundary".  The given solution is to manual fix the citation to not split across the page boundary.  However, this workaround isn't feasible for me, as the documents are automatically generated on a server with no user interaction.  Is there any solution to the problem known, perhaps an experimental hyperref action or a patch to pdftex?  (Probably, one could use luatex to solve the problem, but for other reasons, luatex is not an option in this project.)  MWE:  \documentclass[%draft               ]{article} \usepackage{hyperref} \setlength{\textwidth}{3cm} \setlength{\textheight}{3cm}  \begin{document} Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna \href{http://www.tug.org/errors}{aliquyam erat, sed diam voluptua.} \end{document} Copy files excluding x,y,z causing error in shell script