hendry's questions

Say I have an origin site and structure of media like so:

https://watch.example.com/2017-04-06/training.mp4, which is a static 5GB that will never change.

Now at a remote location with very poor internet, I want to provide a caching proxy which mounts a 4TB disk (that I've sent in advance) that has these files sitting in a directory like /media/2017-04-06/training.mp4, so when the http://cache.local/2017-04-06/training.mp4 is accessed, it plays back the locally cached content. If it fails, the caching proxy might download from https://watch.example.com/2017-04-06/training.mp4 or the media player client might be coded to fallback to the canonical https://watch.example.com/2017-04-06/training.mp4.

So after investigating nginx, it unfortunately saves the content and headers in a md5sum arrangement at proxy_cache_path, which makes my aim to pre-cache or prime the cache by disk difficult.

Is there some other simpler solution I am missing?

I can't quite grok the image [registry-url]/[namespace]/[image]:[tag] URL for a Docker Hub image of mine for AWS ECS.

With the Docker client it's just docker run -it hendry/count.

So what would Docker Hub's URL for the image?

Is it possible to launch an EC2 instance and associate an IP address in one step? Or does one need to manually do it after it's up?

I heard (perhaps wrongly) that using an Amazon Elastic IP "EIP" on a network interface and attaching that to an EC2 instance might be a quicker way of bringing up (or switching to) a new machine.

However I am little confused how to handle the networking once the new eth1 is attached. Do people have a eth1 systemd networkd rule with a low RouteMetric or do they remove eth0, or they just alter the route or am I missing a trick?

Ultimately since ELB can't have a static IP address, I am looking for ways of making sure EC2 can be quickly provisioned to avoid down time.

With Digital Ocean, I'm able to set a fully qualified domain name before starting it and I sorely miss this feature with AWS EC2.

Currently I manually go into a newly started Ubuntu 16.04 LTS instance and:

1. sudo hostnamectl set-hostname myhost.example.com
2. sudo vim /etc/hosts and append myhost.example.com to the 127.0.0.1 line
3. Optionally goto Route 53 panel & set it up if I want it to resolve
4. And then run the chef scripts.

Am I missing a trick? I can't see any Route 53 / EC2 integration either.

I cannot seem to work out how to protect a symbolic symlink from being deleted/removed or overwritten. Any ideas?

I'm looking to setup DNS failover for config.webconverger.com and I think Route53 is the best option to get it going.

However I'm confused how to export the DNS zone from Dreamhost to Route 53, without typing in every subdomain into Route53's UI.

Am I missing a trick?

I want to call a command directly from a Nagios service file, instead of passing arguments clumsily to commands.cfg. For example I want do this:

define service {
    service_description           footest
    check_command                 $USER1$/check_http example.com -u   http://example.com/index.html
    use generic-service
    host_name                     example
}

But I get a:

Error: Service check command '/usr/share/nagios/libexec/check_http example.com -u http://example.com/index.html' specified in service 'footest' for host 'example' not defined anywhere!

I have Apache rules for a Web application that look like so:

RewriteEngine On
RewriteRule ^unsubscribe/([-A-z0-9]+)/?(.*)$ /list/unsubscribe.php?id=$1&why=$2 [L,QSA]
RewriteRule ^unsub/([-A-z0-9]+)/?(.*)$ /list/subscribe.php?id=$1&why=$2 [L,QSA]

I've tried:

rewrite ^unsubscribe/([-A-z0-9]+)/?(.*)$ /list/unsubscribe.php?id=$1&why=$2;

Which didn't seem to match and results in a 404.

    location /unsubscribe {
        rewrite ^/unsubscribe/([-A-z0-9]+)/?(.*)$ /list/unsubscribe.php?id=$1&why=$2 break;
    }

Results in serving the file, but without PHP processed http://sg.hackandtell.org/unsubscribe/foo/bar

Perhaps can someone recommend some debug strategies?

I have freeradius 2.1.12+dfsg-1.2 working and logging accounting packets to /var/log/freeradius/radacct/detail-20130401.

However I need to tail the log and I want to ideally tail a single log file and manage the logs with logrotate.

What do I change to make it log to just /var/log/freeradius/radacct/detail instead?

On Debian 7.0 I've setup filesystem access control lists on my mount

mx:/srv/www$ mount | grep acl
/dev/xvda on / type ext3 (rw,relatime,errors=remount-ro,acl,data=ordered)

Now I simply want newly created files and dirs to have the www-data group.

sudo setfacl -Rm d:g:www-data:rX,g:www-data:rX /srv/www/

Now it has the settings:

mx:/srv/www$ getfacl .                                                                                                                                                    
# file: .
# owner: hendry
# group: root
user::rwx
group::r-x
group:www-data:r-x
mask::r-x
other::r-x
default:user::rwx
default:group::r-x
default:group:www-data:r-x
default:mask::r-x
default:other::r-x

To test, I did a:

mx:/srv/www$ touch test
mx:/srv/www$ ll test
-rw-r--r--+ 1 hendry hendry 0 Mar 19 07:25 test

I was expecting to see hendry:www-data upon the newly created file test. What am I missing?

I use a very simple /etc/apache2/sites-enabled/000-default configuration like

<VirtualHost 117.121.241.184>
UseCanonicalName    Off
VirtualDocumentRoot /srv/www/%0
Options All ExecCGI
LogFormat "%V %h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" vhost_common
CustomLog /var/log/apache2/access.log vhost_common
</VirtualHost>

Where 117.121.241.184 is the IP of my machine I'm setting upon.

Now I want to do something a little complicated, i.e. proxy a NodeJS instance like so:

<VirtualHost foobar.example.com:80>
 <Location />
   ProxyPass http://localhost:3000/
   ProxyPassReverse http://localhost:3000/
 </Location>
</VirtualHost>

And it doesn't work. Apache just serves /srv/www/foobar.example.com. If I put the "VirtualHost foobar.example.com" stanza above the VirtualDocumentRoot one, then everything gets redirected to the proxy, which I don't want.

I just want the particular domain "foobar.example.com" handled by the proxy, and everything else, the VirtualDocumentRoot.

I'm replacing index.cgi of gitweb with a static index.html page.

However I don't want links to gitweb repositories to break, such as http://example.com/?p=foobar;

My non-working .htaccess currently looks like:

DirectoryIndex index.html index.php
RewriteCond %{QUERY_STRING} p
RewriteRule ^/ /index.cgi

What am I missing?

How do I find the network interface that's connected to the Internet?

This machine could typically be connected via {eth0,eth1,usb0,wlan0}. The best I could think of is:

sudo route | grep default | awk '{print $NF}'

Update: My favoured solution is:

 $(for i in `ip r`; do echo $i; done | grep -A 1 dev | tail -n1)

I used Apache's virtual host for a ton of subdomains for greptweet.com, where each twitter username is a subdomain, like <username>.greptweet.com. Problem is ... subdomains can't have underscores! :)

Now I've restructured the site, I want to permanently redirect all users that are going to the subdomain to the path:

<username>.greptweet.com to the path structure greptweet.com/u/<username>

e.g. http://kaihendry.greptweet.com/ to http://greptweet.com/u/kaihendry/

Ideally I'd like to achieve this nearly in the Apache httpd.conf <VirtualHost> stanza instead of writing bits into /srv/www/

I'm using Gmail as a spam filter, whereby it forwards mail to [email protected] and I use mutt to read my email.

However [email protected] accepts mail from everyone currently, so I want to restrict what it accepts to just Google gmail servers. Any recipes for that?

We recently have encountered a problem on our two shared lines provided by Regus in a serviced office.

When there is download on either connection it renders the Internet unusable for anyone. I've noticed this on typical shared connections, though I'm surprised to see it now on two separate lines.

Can someone offer an explanation, advice or solution for providing a more stable connection whilst a download or upload for that matter is in progress?

I hear http://www.isoc.org/ has Domain Name System Security Extensions on its DNS records.

How do I see and verify the DNS using the tool dig?