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curious_george's questions

Martin Hope
curious_george
Asked: 2017-02-18 12:24:57 +0800 CST
  • 0

I recently tried out the Chef Docker container at: https://hub.docker.com/r/chef/chef/

I downloaded it and ran the container using the following commands:

docker pull "chef/chef:12.19.33"
docker run -i -t --name test1 chef/chef:12.19.33

Inside the container, none of the Chef/Knife binaries work. The error says "not found". This is strange. Here is an example of the commands I used:

/ # ls -ltr /opt/chef/bin/knife
-rwxr-xr-x 1 root root 1599 Feb 16 19:28 /opt/chef/bin/knife
/ # /opt/chef/bin/knife
sh: /opt/chef/bin/knife: not found

Does anyone know what is going on? I tried older Chef containers and still got the same issue. I also tried running Docker on other machines.

docker chef knife
Martin Hope
curious_george
Asked: 2015-06-25 23:02:04 +0800 CST
  • 0

I am investigating ways to mitigate a server against DoS-type attacks. In one scenario, I've opened several hundred TCP connections to my webserver. I do not send any data after the initial TCP handshake; it is an idle connection after the TCP handshake. The server shows this connection in the ESTABLISHED state.

After 60 seconds of no activity, the connection is terminated by the server (moved to the FIN_WAIT2 state).

Why does this happen after 60 seconds? Is there a kernel value that controls this? I expected the connection to terminate after "tcp_keepalive_time" seconds (currently set to 7200).

It's good that the idle connection does not have to wait 7200 seconds to get terminated, but I want to understand why it happens after 60 seconds.

This is on a CentOS 6.4 server running the 2.6.32 kernel.

security
Martin Hope
curious_george
Asked: 2011-03-05 09:57:08 +0800 CST
  • 5

I am using the "date" command to perform some simple date arithmetic. The "-d" option lets me do this, but the man pages are very unclear on what is valid data. What are all the accepted options, and how do I figure that out?

I can use this command to determine the date 5 minutes ago: date -d "5-minutes-ago" +%H:%M

This command also works: date -d "-5 minutes" +%H:%M

I stumbled upon these options by accident/frustration. I don't see a "minutes-ago" or a "-X minutes" option listed in the documentation.

I would use Perl to do the arithmetic, but unfortunately I cannot install any additional Perl packages.

date