Andrei Serdeliuc's questions -server

Andrei Serdeliuc

Asked: 2013-08-23 09:11:02 +0800 CST

build-essential: no installation candidate sometimes

5

I'm having a reoccurring issue when sometimes build-essential isn't available while trying to setup ubuntu 12.04.2 on AWS (using ubuntu provided ami: ami-ce7b6fba).

Script that sets up the instance:

set -o xtrace
set -e

sudo apt-get update
sudo apt-get -y install build-essential

The fairly annoying bit is that it sometimes works. I have tried to add the eu-west-1 ubuntu mirror, but that didn't solve the issue.

Any ideas?

The output:

amazon-ebs: ++ set -e
amazon-ebs: ++ sudo apt-get update
amazon-ebs: Get:1 http://security.ubuntu.com precise-security Release.gpg [198 B]
amazon-ebs: Hit http://archive.ubuntu.com precise Release.gpg
amazon-ebs: Get:2 http://security.ubuntu.com precise-security Release [49.6 kB]
amazon-ebs: Get:3 http://archive.ubuntu.com precise-updates Release.gpg [198 B]
amazon-ebs: Hit http://archive.ubuntu.com precise Release
amazon-ebs: Get:4 http://archive.ubuntu.com precise-updates Release [49.6 kB]
amazon-ebs: Hit http://archive.ubuntu.com precise/main amd64 Packages
amazon-ebs: Get:5 http://security.ubuntu.com precise-security/main amd64 Packages [309 kB]
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/universe amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/main i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/universe i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/main TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/universe TranslationIndex
amazon-ebs: Get:6 http://security.ubuntu.com precise-security/restricted amd64 Packages [4627 B]
amazon-ebs: Get:7 http://archive.ubuntu.com precise-updates/main amd64 Packages [677 kB]
amazon-ebs: Get:8 http://security.ubuntu.com precise-security/universe amd64 Packages [80.9 kB]
amazon-ebs: Get:9 http://security.ubuntu.com precise-security/multiverse amd64 Packages [2442 B]
amazon-ebs: Get:10 http://security.ubuntu.com precise-security/main i386 Packages [325 kB]
amazon-ebs: Get:11 http://security.ubuntu.com precise-security/restricted i386 Packages [4620 B]
amazon-ebs: Get:12 http://security.ubuntu.com precise-security/universe i386 Packages [84.1 kB]
amazon-ebs: Get:13 http://archive.ubuntu.com precise-updates/restricted amd64 Packages [11.5 kB]
amazon-ebs: Get:14 http://security.ubuntu.com precise-security/multiverse i386 Packages [2633 B]
amazon-ebs: Get:15 http://archive.ubuntu.com precise-updates/universe amd64 Packages [211 kB]
amazon-ebs: Get:16 http://security.ubuntu.com precise-security/main TranslationIndex [74 B]
amazon-ebs: Get:17 http://security.ubuntu.com precise-security/multiverse TranslationIndex [72 B]
amazon-ebs: Get:18 http://archive.ubuntu.com precise-updates/multiverse amd64 Packages [13.8 kB]
amazon-ebs: Get:19 http://security.ubuntu.com precise-security/restricted TranslationIndex [72 B]
amazon-ebs: Get:20 http://archive.ubuntu.com precise-updates/main i386 Packages [698 kB]
amazon-ebs: Get:21 http://security.ubuntu.com precise-security/universe TranslationIndex [73 B]
amazon-ebs: Get:22 http://security.ubuntu.com precise-security/main Translation-en [149 kB]
amazon-ebs: Get:23 http://archive.ubuntu.com precise-updates/restricted i386 Packages [11.4 kB]
amazon-ebs: Get:24 http://archive.ubuntu.com precise-updates/universe i386 Packages [215 kB]
amazon-ebs: Get:25 http://security.ubuntu.com precise-security/multiverse Translation-en [1299 B]
amazon-ebs: Get:26 http://archive.ubuntu.com precise-updates/multiverse i386 Packages [14.0 kB]
amazon-ebs: Hit http://security.ubuntu.com precise-security/restricted Translation-en
amazon-ebs: Get:27 http://archive.ubuntu.com precise-updates/main TranslationIndex [3564 B]
amazon-ebs: Get:28 http://security.ubuntu.com precise-security/universe Translation-en [51.8 kB]
amazon-ebs: Get:29 http://archive.ubuntu.com precise-updates/multiverse TranslationIndex [2605 B]
amazon-ebs: Get:30 http://archive.ubuntu.com precise-updates/restricted TranslationIndex [2461 B]
amazon-ebs: Get:31 http://archive.ubuntu.com precise-updates/universe TranslationIndex [2850 B]
amazon-ebs: Get:32 http://archive.ubuntu.com precise/main Translation-en [726 kB]
amazon-ebs: Get:33 http://archive.ubuntu.com precise/multiverse Translation-en [93.4 kB]
amazon-ebs: Get:34 http://archive.ubuntu.com precise/restricted Translation-en [2395 B]
amazon-ebs: Get:35 http://archive.ubuntu.com precise/universe Translation-en [3341 kB]
amazon-ebs: Get:36 http://archive.ubuntu.com precise-updates/main Translation-en [306 kB]
amazon-ebs: Get:37 http://archive.ubuntu.com precise-updates/multiverse Translation-en [8064 B]
amazon-ebs: Get:38 http://archive.ubuntu.com precise-updates/restricted Translation-en [2637 B]
amazon-ebs: Get:39 http://archive.ubuntu.com precise-updates/universe Translation-en [125 kB]
amazon-ebs: Fetched 7582 kB in 8s (930 kB/s)
amazon-ebs: Reading package lists... Done
amazon-ebs: ++ sudo apt-get -y install build-essential
amazon-ebs: Reading package lists... Done
amazon-ebs: Building dependency tree
amazon-ebs: Reading state information... Done
amazon-ebs: Package build-essential is not available, but is referred to by another package.
amazon-ebs: This may mean that the package is missing, has been obsoleted, or
amazon-ebs: is only available from another source
amazon-ebs:
amazon-ebs: E: Package 'build-essential' has no installation candidate

And when it works:

amazon-ebs: ++ set -e
amazon-ebs: ++ sudo apt-get update
amazon-ebs: Get:1 http://security.ubuntu.com precise-security Release.gpg [198 B]
amazon-ebs: Hit http://archive.ubuntu.com precise Release.gpg
amazon-ebs: Get:2 http://security.ubuntu.com precise-security Release [49.6 kB]
amazon-ebs: Get:3 http://archive.ubuntu.com precise-updates Release.gpg [198 B]
amazon-ebs: Hit http://archive.ubuntu.com precise Release
amazon-ebs: Get:4 http://archive.ubuntu.com precise-updates Release [49.6 kB]
amazon-ebs: Hit http://archive.ubuntu.com precise/main amd64 Packages
amazon-ebs: Get:5 http://security.ubuntu.com precise-security/main amd64 Packages [309 kB]
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/universe amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse amd64 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/main i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/universe i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse i386 Packages
amazon-ebs: Hit http://archive.ubuntu.com precise/main TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted TranslationIndex
amazon-ebs: Hit http://archive.ubuntu.com precise/universe TranslationIndex
amazon-ebs: Get:6 http://archive.ubuntu.com precise-updates/main amd64 Packages [677 kB]
amazon-ebs: Get:7 http://archive.ubuntu.com precise-updates/restricted amd64 Packages [11.5 kB]
amazon-ebs: Get:8 http://archive.ubuntu.com precise-updates/universe amd64 Packages [211 kB]
amazon-ebs: Get:9 http://archive.ubuntu.com precise-updates/multiverse amd64 Packages [13.8 kB]
amazon-ebs: Get:10 http://archive.ubuntu.com precise-updates/main i386 Packages [698 kB]
amazon-ebs: Get:11 http://security.ubuntu.com precise-security/restricted amd64 Packages [4627 B]
amazon-ebs: Get:12 http://security.ubuntu.com precise-security/universe amd64 Packages [80.9 kB]
amazon-ebs: Get:13 http://security.ubuntu.com precise-security/multiverse amd64 Packages [2442 B]
amazon-ebs: Get:14 http://security.ubuntu.com precise-security/main i386 Packages [325 kB]
amazon-ebs: Get:15 http://archive.ubuntu.com precise-updates/restricted i386 Packages [11.4 kB]
amazon-ebs: Get:16 http://archive.ubuntu.com precise-updates/universe i386 Packages [215 kB]
amazon-ebs: Get:17 http://security.ubuntu.com precise-security/restricted i386 Packages [4620 B]
amazon-ebs: Get:18 http://security.ubuntu.com precise-security/universe i386 Packages [84.1 kB]
amazon-ebs: Get:19 http://archive.ubuntu.com precise-updates/multiverse i386 Packages [14.0 kB]
amazon-ebs: Get:20 http://security.ubuntu.com precise-security/multiverse i386 Packages [2633 B]
amazon-ebs: Get:21 http://security.ubuntu.com precise-security/main TranslationIndex [74 B]
amazon-ebs: Get:22 http://security.ubuntu.com precise-security/multiverse TranslationIndex [72 B]
amazon-ebs: Get:23 http://archive.ubuntu.com precise-updates/main TranslationIndex [3564 B]
amazon-ebs: Get:24 http://security.ubuntu.com precise-security/restricted TranslationIndex [72 B]
amazon-ebs: Get:25 http://archive.ubuntu.com precise-updates/multiverse TranslationIndex [2605 B]
amazon-ebs: Get:26 http://security.ubuntu.com precise-security/universe TranslationIndex [73 B]
amazon-ebs: Get:27 http://archive.ubuntu.com precise-updates/restricted TranslationIndex [2461 B]
amazon-ebs: Get:28 http://security.ubuntu.com precise-security/main Translation-en [149 kB]
amazon-ebs: Get:29 http://archive.ubuntu.com precise-updates/universe TranslationIndex [2850 B]
amazon-ebs: Hit http://archive.ubuntu.com precise/main Translation-en
amazon-ebs: Hit http://archive.ubuntu.com precise/multiverse Translation-en
amazon-ebs: Hit http://archive.ubuntu.com precise/restricted Translation-en
amazon-ebs: Get:30 http://security.ubuntu.com precise-security/multiverse Translation-en [1299 B]
amazon-ebs: Hit http://security.ubuntu.com precise-security/restricted Translation-en
amazon-ebs: Hit http://archive.ubuntu.com precise/universe Translation-en
amazon-ebs: Get:31 http://security.ubuntu.com precise-security/universe Translation-en [51.8 kB]
amazon-ebs: Get:32 http://archive.ubuntu.com precise-updates/main Translation-en [306 kB]
amazon-ebs: Get:33 http://archive.ubuntu.com precise-updates/multiverse Translation-en [8064 B]
amazon-ebs: Get:34 http://archive.ubuntu.com precise-updates/restricted Translation-en [2637 B]
amazon-ebs: Get:35 http://archive.ubuntu.com precise-updates/universe Translation-en [125 kB]
amazon-ebs: Fetched 3420 kB in 2s (1637 kB/s)
amazon-ebs: Reading package lists... Done
amazon-ebs: ++ sudo apt-get -y install build-essential
amazon-ebs: Reading package lists... Done
amazon-ebs: Building dependency tree
amazon-ebs: Reading state information... Done
amazon-ebs: The following extra packages will be installed:
amazon-ebs: binutils cpp cpp-4.6 dpkg-dev
amazon-ebs: fakeroot g++ g++-4.6 gcc gcc-4.6
amazon-ebs: libalgorithm-diff-perl
amazon-ebs: libalgorithm-diff-xs-perl
amazon-ebs: libalgorithm-merge-perl libc-bin
amazon-ebs: libc-dev-bin libc6 libc6-dev
amazon-ebs: libdpkg-perl libgomp1 libmpc2
amazon-ebs: libmpfr4 libquadmath0
amazon-ebs: libstdc++6-4.6-dev linux-libc-dev
amazon-ebs: make manpages-dev
amazon-ebs: Suggested packages:
amazon-ebs: binutils-doc cpp-doc gcc-4.6-locales
amazon-ebs: debian-keyring g++-multilib
amazon-ebs: g++-4.6-multilib gcc-4.6-doc
amazon-ebs: libstdc++6-4.6-dbg gcc-multilib
amazon-ebs: autoconf automake1.9 libtool flex
amazon-ebs: bison gdb gcc-doc gcc-4.6-multilib
amazon-ebs: libmudflap0-4.6-dev libgcc1-dbg
amazon-ebs: libgomp1-dbg libquadmath0-dbg
amazon-ebs: libmudflap0-dbg binutils-gold
amazon-ebs: glibc-doc libstdc++6-4.6-doc
amazon-ebs: make-doc
amazon-ebs: The following NEW packages will be installed:
amazon-ebs: binutils build-essential cpp cpp-4.6
amazon-ebs: dpkg-dev fakeroot g++ g++-4.6 gcc
amazon-ebs: gcc-4.6 libalgorithm-diff-perl
amazon-ebs: libalgorithm-diff-xs-perl
amazon-ebs: libalgorithm-merge-perl libc-dev-bin
amazon-ebs: libc6-dev libdpkg-perl libgomp1
amazon-ebs: libmpc2 libmpfr4 libquadmath0
amazon-ebs: libstdc++6-4.6-dev linux-libc-dev
amazon-ebs: make manpages-dev
amazon-ebs: The following packages will be upgraded:
amazon-ebs: libc-bin libc6
amazon-ebs: 2 upgraded, 24 newly installed, 0 to remove and 76 not upgraded

When it doesn't work, sudo wc -l /var/lib/dpkg/available returns:

9280 /var/lib/dpkg/available

Andrei Serdeliuc

Asked: 2013-08-03 06:24:33 +0800 CST

Puppet variables best practice, generalise or specialise?

2

I'm trying to figure out which things should be in git within the puppet manifest and which should be in env vars like FACTER_my_var and use that in the manifest instead.

Scenario: you are deploying 3 php apps and you've already built all the layers up to the app in other manifests (base system, php extensions, users, etc), and all that's left is installing the correct app (from an apt repo) and creating a vhost.

I'm tempted to have something along the lines of:

apache::vhost { $::project_hostname:
    priority => '10',
    port => '80',
    docroot => $::project_document_root,
    logroot => "/var/log/apache2/${$::project_name}",
    serveradmin => '[email protected]',
    require => Package[httpd],
    ssl => false,
    override => 'all',
    setenv => ["APP_KERNEL dev"]
}

This would run on each server, and the FACTER_project_* vars would be set on a per server basis. An obvious restriction of this would be that you can't run more than one app with this specific example.

Or would you rather have project_x.pp, project_y.pp which have hardcoded paths and names?

Andrei Serdeliuc

Asked: 2012-09-28 07:45:33 +0800 CST

nginx lua: os.execute waitpid() failed (10: No child processes)

8

So, I'm trying to execute a script on every request. I know how that sounds, this is for development environment.

I've added this to my nginx config access_by_lua_file "/opt/nginx/git-magic.lua";

git-magic.lua contains local status = os.execute('/opt/nginx/git-magic.sh')

And git-magic.sh contains: echo hello >> /tmp/git-magic

The issue is:

Whenever I hit any URL, I get the following in the nginx error log: 2012/09/27 15:35:48 [alert] 3241#0: waitpid() failed (10: No child processes)

Any ideas what I might be doing wrong?

Andrei Serdeliuc

Asked: 2012-06-21 07:30:03 +0800 CST

How would you simplify this command?

10

I'm quite new to strace / netstat / etc. I'm using this command to get a trace of the apache process handling my request (telnet), is there a way to simplify it a bit?

sudo strace -o /tmp/strace -f -s4096 -r -p $(netstat -antlp | \ 
    grep $(lsof -p `pidof telnet` | grep TCP | \
    perl -n -e'/localhost:(\d+)/ && print $1') | grep apache2 | \ 
    perl -n -e'/ESTABLISHED (\d+)/ && print $1')

Thanks!

Andrei Serdeliuc

Asked: 2012-05-06 03:08:39 +0800 CST

Tmux send-keys stripping space

8

I'm trying to run a series of commands in tmux from a remote file like so:

tmux $(wget -qO- http://example.com/tmux)

The file contains commands like split-window and send-keys

The problem is, send-keys is stripping spaces. The send-keys commands is:

send-keys ssh example.com C-m;

But instead it sends sshexample.com

Any idea why?

Cheers!

Andrei Serdeliuc

Asked: 2012-03-29 03:53:35 +0800 CST

Puppet: hanging at Schedule[weekly]

2

Why would puppet hang at Schedule[weekly]?

I'm running puppet in a masterless setup, so to apply by manifest I'm just running puppet apply /etc/puppet/manifests/site.pp

In debug mode, these are the last things it says before it just hangs

debug: /Schedule[never]: Skipping device resources because running on a host
debug: /Schedule[daily]: Skipping device resources because running on a host
debug: /Schedule[monthly]: Skipping device resources because running on a host
debug: /Schedule[puppet]: Skipping device resources because running on a host
debug: /Schedule[hourly]: Skipping device resources because running on a host
debug: /Schedule[weekly]: Skipping device resources because running on a host

If I send a SIGINT, it says

Exiting
debug: Storing state
debug: Stored state in 0.03 seconds
debug: Finishing transaction 69992657242500

Thanks

Andrei Serdeliuc

Asked: 2012-02-18 03:23:33 +0800 CST

Nginx multiple location issues

18

I'm currently trying to break apart 3 applications from one repository into 3, but keeping the url structure, so basically different locations under the same domain have to be delivered by different applications.

What I'm struggling with is that one of the apps needs to be the fallback for non-existent urls, so if the first one doesn't match, and the second one doesn't, then the third should handle the request

The structure I've got is:

/etc/nginx/sites-enabled/main_site, in here, apart from server_name and logs I've got include /etc/nginx/subsites-enabled/*, where I've got 3 configuration files, one for each of the apps.

Each of the 3 config files contains a location block.

I've tried negative lookahead in regex (basically trying to hardcode the urls the other apps handle) but failed.

So, to summarise:

/ and /community should be delivered by /etc/nginx/subsites-enabled/example.org/home (a few perl scripts)

/news should be delivered by /etc/nginx/subsites-enabled/example.org/news (wordpress)

everything else should be delivered by /etc/nginx/subsites-enabled/example.org/app (cake app)

The perl bit works fine. The problem I'm having is that the app is taking over news (probably because it matches .*), I've tried various options (I've been at this for 2 days) but none of them solved all the problems (sometimes static assets wouldn't work, etc).

My configuration is:

/etc/nginx/sites-enabled/example.org:

server {
    listen   80;
    server_name example.org;
    error_log /var/log/nginx/example.org.log;

    include /etc/nginx/subsites-enabled/example.org/*;
}

/etc/nginx/subsites-enabled/example.org/home:

location = / {
  rewrite ^.*$ /index.pl last;
}

location ~* /community(.*) {
  rewrite ^.*$ /index.pl last;
}

location ~ \.pl {
  root   /var/www/vhosts/home;
  access_log /var/log/nginx/home/access.log;
  error_log /var/log/nginx/home/error.log;

  include /etc/nginx/fastcgi_params;
  fastcgi_index index.pl;
  fastcgi_param SCRIPT_FILENAME /var/www/vhosts/home$fastcgi_script_name;
  fastcgi_pass  unix:/var/run/fcgiwrap.socket;
}

/etc/ngins/subsites-enabled/news

location /news {
  access_log /var/log/nginx/news/access.log;
  error_log /var/log/nginx/news/error.log debug;

  error_page 404 = /news/index.php;

  root /var/www/vhosts/news;

  index index.php;

  if (!-e $request_filename) {
      rewrite ^.*$ /index.php last;
  }

  location ~ \.php {
    include /etc/nginx/fastcgi_params;
    fastcgi_pass  127.0.0.1:9000;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME /var/www/vhosts/news$fastcgi_script_name;
  }
}

/etc/nginx/subsites-enabled/app:

location ~ .* {
  access_log /var/log/nginx/app/access.log;
  error_log /var/log/nginx/app/error.log;

  rewrite_log on;

  index index.php;
  root /var/www/vhosts/app/app/webroot;

  if (-f $request_filename) {
    expires 30d;
    break;
  }

  if (!-e $request_filename) {
    rewrite ^.*$ /index.php last;
  }

  location ~ \.php {
    include /etc/nginx/fastcgi_params;
    fastcgi_pass  127.0.0.1:9000;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME /var/www/vhosts/app/app/webroot$fastcgi_script_name;
  }
}

Andrei Serdeliuc

Asked: 2012-02-08 04:08:36 +0800 CST

Puppet: stage main not found?

0

I'm trying to use this RVM puppet module, but puppet is complaining that it can't find Stage[main]:

Could not find stage main specified by Class[Rvm] at /etc/puppet/modules/rvm/manifests/system.pp:3

Has anyone encountered this in the past?

Thanks!

Andrei Serdeliuc

Asked: 2012-02-01 04:26:10 +0800 CST

Use puppet to set hostname?

14

Is there any way of setting a server's hostname using puppet?

I could write a custom type, but maybe there's a simpler way.

Thanks

[Edit] Sorry, I should've mentioned I run puppet masterless, puppet is setup first and then it sets up everything else.

Andrei Serdeliuc

Asked: 2011-04-09 01:49:08 +0800 CST

Linux CNAME without nameserver

1

Is there a way to setup CNAMEs without using an actual nameserver? This is for testing purposes on EC2 so any (hacky?) way of doing it would be good.

Or, if there's a light DNS server that's easy to configure, that'd be good as well.

I'm running Ubuntu 11.04 on EC2

Andrei Serdeliuc

Asked: 2011-03-13 09:29:25 +0800 CST

Central authentication and public key store?

4

What would the best solution be for central authentication?

I want to store all of our users centrally and use that for SSH access and other services. I also want our users to be able to authenticate on their machines (mostly macs) using the same authentication server.

Currently we use SSH with public keys, but each user generates their own keys and they add them themselves on our servers. This becomes hard to manage when we get new employees or others leave.

I need passwordless authentication though, as I don't trust users in creating their own passwords.

What other options are there apart from LDAP? All of our servers are running some flavour of Linux.

Thanks

Andrei Serdeliuc

Asked: 2011-01-28 05:47:00 +0800 CST

Store each database in a different directory

4

Is there any way to store each mysql database in a separate directory? I could symlink the directories into /var/lib/mysql for each database, but I was wondering if there is a built-in way of doing it.

Thanks

Andrei Serdeliuc

Asked: 2010-10-14 03:59:29 +0800 CST

Varnish 503 when delivering a slow page

3

Varnish keeps throwing 503 Service Unavailable when trying to load a page that takes longer to generate on the web server.

In varnishlog I can see an FetchError c http read error: 0 error, though I'm not quite sure what it means.

I also tried increasing the backend timeouts:

backend default {
    .host = "x.x.x.x";
    .port = "80";
    .connect_timeout = 600s;
    .first_byte_timeout = 600s;
    .between_bytes_timeout = 600s;
}

The backend is an Apache server.

All other pages work fine.

Any ideas?

Andrei Serdeliuc

Asked: 2010-09-02 03:08:21 +0800 CST

Forward FTP to another server using iptables

0

My setup is:

FTP client -> proxy server (eth0: external, eth1: internal) -> FTP server (eth1:internal)

I'm trying to forward all FTP traffic from the proxy server on eth0 to the FTP server on eth1.

After about 2 hours of google and serverfault, iptables-save currently outputs:

# Generated by iptables-save v1.4.4 on Wed Sep  1 11:00:51 2010
*mangle
:PREROUTING ACCEPT [16444:5734756]
:INPUT ACCEPT [16271:5724316]
:FORWARD ACCEPT [169:10240]
:OUTPUT ACCEPT [10273:6431264]
:POSTROUTING ACCEPT [10475:6447560]
COMMIT
# Completed on Wed Sep  1 11:00:51 2010
# Generated by iptables-save v1.4.4 on Wed Sep  1 11:00:51 2010
*filter
:INPUT ACCEPT [1310:105993]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [713:80204]
-A FORWARD -i eth0 -o eth1 -p tcp -m tcp --dport 21 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT 
COMMIT
# Completed on Wed Sep  1 11:00:51 2010
# Generated by iptables-save v1.4.4 on Wed Sep  1 11:00:51 2010
*nat
:PREROUTING ACCEPT [271:15644]
:POSTROUTING ACCEPT [1410:86453]
:OUTPUT ACCEPT [1391:85237]
-A PREROUTING -d xxx.xxx.xxx.xxx/32 -p tcp -m tcp --dport 21 -m state --state NEW,RELATED,ESTABLISHED -j DNAT --to-destination xxx.xxx.xxx.xxx:21 
COMMIT
# Completed on Wed Sep  1 11:00:51 2010

The first ip in prerouting is the external ip of the proxy server, the 2nd ip is the internal ip of the ftp server.

Trying to connect directly to the FTP server works fine, trying to connect to the proxy server though, doesn't do anything (just times out).

Any pointers on what I'm doing wrong?

Thanks!

Andrei Serdeliuc

Asked: 2010-08-20 06:01:16 +0800 CST

Ubuntu server - record audio

0

Is there any way to record audio on Ubuntu server? I've got Ubuntu on an old Acer Aspire 5520g but I'm not sure where to start with recording audio on it.

Andrei Serdeliuc

Asked: 2010-06-03 14:32:40 +0800 CST

Implementing dry-run in bash scripts

20

How would one implement a dry-run option in a bash script?

I can think of either wrapping every single command in an if and echoing out the command instead of running it if the script is running with dry-run.

Another way would be to define a function and then passing each command call through that function.

Something like:

function _run () {
    if [[ "$DRY_RUN" ]]; then
        echo $@
    else
        $@
    fi
}

`_run mv /tmp/file /tmp/file2`

`DRY_RUN=true _run mv /tmp/file /tmp/file2`

Is this just wrong and there is a much better way of doing it?

Andrei Serdeliuc

Asked: 2010-06-03 02:59:25 +0800 CST

502: proxy: pass request body failed

2

Sometimes I get the following error (in apache's error.log) when viewing my site over https:

(502)Unknown error 502: proxy: pass request body failed to xxx.xxx.xxx.xxx:443

I'm not entirely sure what this is and why it happens, it's also not consistent.

The request route is:

Browser
Proxy server (apache with mod_proxy + mod_ssl)
Load balancer (aws)
Web server (apache with mod_ssl)

The configuration on the proxy server is as follows:

<VirtualHost *:443>
    ProxyRequests Off
    ProxyVia On

    ServerName                      www.xxx.co.uk
    ServerAlias                     xxx.co.uk

    <Directory proxy:*>
        Order deny,allow
        Allow from all
    </Directory>

    <Proxy *>
        AddDefaultCharset off
        Order deny,allow
        Allow from all
    </Proxy>

    ProxyPass / balancer://cluster:443/ lbmethod=byrequests
    ProxyPassReverse / balancer://cluster:443/
    ProxyPreserveHost off

    SSLProxyEngine On
    SSLEngine on
    SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
    SSLCertificateFile /var/www/vhosts/xxx/ssl/www.xxx.co.uk.cert
    SSLCertificateKeyFile /var/www/vhosts/xxx/ssl/www.xxx.co.uk.key

    <Proxy balancer://cluster>
        BalancerMember https://xxx.eu-west-1.elb.amazonaws.com
    </Proxy>

</VirtualHost>

Any idea what the issue might be?

Andrei Serdeliuc

Asked: 2010-06-02 01:57:37 +0800 CST

ls hangs after NFS server reboot

1

I've got server A and server B. B acts as an nfs server, A mounts from B.

Both are running on EC2.

Sometimes I have to shut down B and start a new instance (identical instance). After B is back up, trying to do anything inside the mounted directory on A (ls for example) just hangs.

I'm trying to set up a cron that checks the status of the mount, and remounts if anything is wrong.

Is there any way to check the status of a mount?

Andrei Serdeliuc

Asked: 2010-02-25 07:07:45 +0800 CST

Apache jamming at low load average

0

Apache seems to stop responding sometimes even though apache processes are still running.

After restarting apache, the load average usually shoots up from 1 - 2 to 13 - 15 in a matter of seconds.

What would the cause of this be, or how could I find out why apache stops serving?

My httpd.conf is:

<IfModule mpm_prefork_module>
    StartServers          8
    MinSpareServers       5
    MaxSpareServers      20
    MaxClients          50
    ServerLimit         50
    MaxRequestsPerChild   4000
</IfModule>

It's running on an EC2 c1.medium (1.7 GB of memory)

Thanks

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