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1500 questions
74
votes
4 answers
Why disable swap on kubernetes
Since Kubernetes 1.8, it seems I need to disable swap on my nodes (or set --fail-swap-on to false).
I cannot find the technical reason why Kubernetes insists on the swap being disabled. Is this for performance reasons? Security reasons? Why is the…
Jeroen Jacobs
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74
votes
8 answers
Why is the response on localhost so slow?
I am working on a tiny little PHP project for a friend of mine, and I have a WAMP environment setup for local development. I remember the days when the response from my local Apache 2.2 was immediate. Alas, now that I got back from a long, long…
Peter Perháč
- 1,069
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- 9
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74
votes
4 answers
SSH key authentication using LDAP
In short:
Would like a way to do SSH key authentication via LDAP.
Problem:
We use LDAP (slapd) for directory services and we've recently moved to using our own AMI for building instances. The reason the AMI bit is important is that, ideally, we…
c4urself
- 5,530
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74
votes
14 answers
Docker containers can't resolve DNS on Ubuntu 14.04 Desktop Host
I'm running into a problem with my Docker containers on Ubuntu 14.04 LTS.
Docker worked fine for two days, and then suddenly I lost all network connectivity inside my containers. The error output below initially lead me to believe it was because…
Thomas V.
- 2,071
- 2
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74
votes
5 answers
What is the correct way to open a range of ports in iptables
I have come across articles advising for the following:
iptables -A INPUT -p tcp 1000:2000 -j ACCEPT
And others stating that the above will not work and iptables only supports multiple port declarations with the --multiport option.
Is there a…
Paul Whalley
- 763
- 1
- 7
- 6
74
votes
7 answers
How to specify hostname for the running container?
I'm having trouble setting the hostname on a running docker container. I'm also having trouble understanding how to specify hostname after the image is started.
I started a container from an image I downloaded:
sudo docker run -p 8080:80 -p 2222:22…
Miguel Ping
- 865
- 1
- 6
- 9
74
votes
10 answers
Can I specify a port in an entry in my /etc/hosts on OS X?
Possible Duplicate:
How to use DNS to redirect domain to specific port on my server
I want to trick my browser into going to localhost:3000 instead of xyz.com. I went into /etc/hosts on OS X 10.5 and added the following entry:
127.0.0.1:3000…
Tony
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- 11
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74
votes
3 answers
What is the difference between /sbin/nologin and /bin/false?
I have often heard it recommended that a user account should be disabled by setting its shell to /bin/false. But, on my existing Linux systems, I see that a great number of existing accounts (all of them service accounts) have a shell of…
Michael Hampton
- 244,070
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- 506
- 972
74
votes
2 answers
How should an IT department choose a standard Linux distribution?
There is a lot of community feeling about what Linux distributions are appropriate for production server environments and which aren't, however, a lot of this feeling seems religiously based, and seldom presented with supporting evidence.
Assuming…
wfaulk
- 6,878
- 7
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74
votes
3 answers
How long does negative DNS caching typically last?
If a DNS server looks up a record and it's missing, it will often "negatively cache" the fact that this record is missing, and not try to look it up again for a while. I don't see anything in the RFC about the TTL on negative caching should be, so…
Leopd
- 1,757
- 4
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74
votes
6 answers
How to redirect domain A to domain B using A-Records and CNAME records only
I have 2 domains hosted with different hosts. I need to redirect Domain A to Domain B. Unfortunately I can't do a 301 redirect from Host A, but can only modify/add DNS entries (A-Records and CNAMEs) at Host A.
Surely it is possible to redirect…
Prembo
- 927
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74
votes
6 answers
How to scan local network for SSH-able computers?
I am often on one computer in my house and I would like to SSH to another one, but often don't know the IP address of the one I want to connect to. Is there a way, from the command line, to scan the local network so I can find the computer I want to…
Andrew
- 3,453
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74
votes
4 answers
How to PREPEND rules rather than APPEND using iptables?
Pretty basic question: how to PREPEND rules on IPTABLES rather than to APPEND?
I have DROP statements at the bottom of my rules. I have a software to add new rules but adding rules after DROP statements isn't good. Every time I want to add a new…
ale
- 933
- 2
- 10
- 13
74
votes
5 answers
Dump nginx config from running process?
Apparently, I shouldn't have spent sleepless night trying to debug an application. I wanted to restart my nginx and discovered that its config file is empty. I don't remember truncating it, but fat fingers and reduced attention probably played their…
Sergio Tulentsev
- 843
- 1
- 9
- 9
74
votes
11 answers
Why is SSH password authentication a security risk?
Most guides for OpenSSH configuration advise to disable password authentication in favor of key-based authentication. But in my opinion password authentication has a significant advantage: an ability to connect from absolutely anywhere without a…
Septagram
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- 13