Ali Mezgani's questions

I run a RHEL server with rsyslog to collect my network logs, and by receiving a security bulletin alert I have to upgrade this server.

What is the strategy to upgrade this machine, knowing that many other machine's logs depend on this and on an OS update may be we are faced of many reboots ?

what is the comportment of other machine when rsyslog is not running.

NB: I add that the syslog client are appliances, some kind of SMG. And As known is that the appliance are limited on configuration side and tunning parameters.

I Built an image using flask, nginx and uwsgi.

FROM ubuntu:14.04
MAINTAINER Ali Mezgani <[email protected]>

RUN apt-get update && apt-get -y install python python-dev  python-pip
RUN apt-get -y install supervisor
RUN apt-get -y install  nginx

COPY ./app /app

RUN mkdir /var/log/uwsgi/

RUN pip install -r ./app/requirements.txt

RUN rm -fr /etc/nginx/conf.d/*
RUN rm -fr /etc/nginx/sites-enabled/*

COPY app.conf /etc/supervisor/conf.d/app.conf

RUN echo "daemon off;" >> /etc/nginx/nginx.conf
COPY nginx.conf /etc/nginx/sites-enabled/app.conf

expose 80
CMD ["supervisord", "-n"]
CMD ["nginx"]

Here is the output I get when I try ti start the myapp container.

root@cygne:/data/flask# docker start myapp
Error response from daemon: No such container: myapp
Error: failed to start containers: myapp

And finally here is the status of images I have.

root@cygne:/data/flask# docker images -a
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
<none>              <none>              91c4b97dc883        10 hours ago        434.1 MB
myapp               latest              3b9dd7cc7006        10 hours ago        434.1 MB
<none>              <none>              28f96039d2da        10 hours ago        434.1 MB
<none>              <none>              dbd7d20bb041        10 hours ago        434.1 MB
<none>              <none>              f29621c65c25        10 hours ago        434.1 MB
<none>              <none>              7d6d99d831c4        10 hours ago        434.1 MB
<none>              <none>              948cc751026f        10 hours ago        434.1 MB
<none>              <none>              afc13c68670c        10 hours ago        434.1 MB
<none>              <none>              90733b74c1ff        10 hours ago        434.1 MB
<none>              <none>              f8252e26afe5        10 hours ago        424.4 MB
<none>              <none>              4b16f8a9bfbb        10 hours ago        424.4 MB
<none>              <none>              126961e5d0b2        10 hours ago        418.6 MB
<none>              <none>              713635425c68        10 hours ago        400.1 MB
<none>              <none>              0755786fa8dc        10 hours ago        396.2 MB
<none>              <none>              3bc29edbc3a3        10 hours ago        188 MB
ubuntu              14.04               8f1bd21bd25c        3 weeks ago         188 MB
mysql               5.7                 2fd136002c22        3 weeks ago         378.4 MB

The container wont start, and I've tried many process like cleaning cache, restarting docker. Here is what I have in my syslog :

localhost docker[6111]: time="2016-06-18T15:06:12.826760681Z" level=error msg="Handler for GET /v1.23/containers/myapp/json returned error: No such container: myapp"

I run solr application on a VM with 41G of memory and I saw that the solr consumme a big amount of memory. I appended 16G to the VM in spite of that solr consumme all memory available in 30min. My question is that surely there are a tuning needed please what is it and how can I calculate the memory needed for Solr node ?

I have many VMs on production that run vmware, with vmtools running and the sync between ESXI and hosts is disabled. I run ntp client on all hosts, the OS of hosts is RHEL.

The problem I have is that I get many incidents about loses sync with NTP servers with important latence, please can you tell me what's wrong with my VMs ? and what I have to check to troubleshoot sync between servers ?

The ntp server is reachable and the time is maintened for a while, I get a difference of offset of 4000ms. I thought that the cause of this lose of sync is that the ESXI sychronisation was enabled and there are two sync in each vm but is it not the case.

My question is simple, is it possible to install two different version of gcc on the same red hat machine.

For example : gcc3.4 and gcc4, on red hat 6 ?

I try to upgrade vmware tools on a VM (Red hat Enterprise Linux Server 6.1) the package I try to install is VMwareTools-8.6.10-913593.tar.gz.

In a step of installation I get this error :

No X install found.

Creating a new initrd boot image for the kernel.
ERROR: "/sbin/dracut --force --add-drivers "vmxnet3 vmw_pvscsi vmxnet"
/boot/initramfs-2.6.32-131.0.15.el6.x86_64.img >/dev/null 2>&1" exited with
non-zero status.

Your system currently may not have a functioning init image and may not boot
properly. DO NOT REBOOT! Please ensure that you have enough free space
available in your /boot directory and run this configuration script again.

Execution aborted.

I'm trying to deploy an application for a limited monthly traffic. Please can you tell me how can I do this ? I need to limit traffic on an interface under linux.

I've set an EasyVPN on a cisco, when connected to the vpn i'm unable to use internet even the default route is through the tun0 interface created by my VPN client vpnc.

Please how to connect to VPN and have internet ? to browse others sites ?

I import a database, and when i run mytop i see only one thread running an insert. On a big database of 80G that will take really big time, is there any tools or may be an option to increase number of threads ?

I setup a gre tunnel a cisco router and a Linux machine, the tunnel interface in the Linux box named pic. Well i have to forward traffic coming from cisco through the Linux box. the rules i've set in the Linux box is described as follow:

echo "1" > /proc/sys/net/ipv4/ip_forward
iptables  -A INPUT -p 47 -j ACCEPT
iptables  -A FORWARD -i ppp0 -j ACCEPT
iptables  -A FORWARD -i pic  -o ppp0 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables  -A FORWARD -i ppp0 -o pic -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables  -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE

May i miss something like a routing rule.

I have a LAN and i need to create a LAB with three VLAN on my boxes, Linux and FreeBSD.

Well i create a VLAN 1 on the linux box as follow:

sudo vconfig add eth0 1
sudo ifconfig eth0.1 inet6 add 2001:470:9b36:2::2/64

and i do the same on the FreeBSD box:

sudo ifconfig vlan1 create
sudo ifconfig vlan1 inet6 2001:470:9b36:2::1 prefixlen 64 vlan 1 vlandev bge0

ifconfig of FreeBSD box

vlan2: flags=8843 metric 0 mtu 1500
    options=3
    ether 00:11:85:61:90:f2
    inet6 fe80::211:85ff:fe61:90f2%vlan2 prefixlen 64 scopeid 0x5 
    inet6 2001:470:9b36:2::1 prefixlen 64 
    inet 10.0.0.1 netmask 0xffffff00 broadcast 10.0.0.255
    nd6 options=3
    media: Ethernet autoselect (100baseTX )
    status: active
    vlan: 2 parent interface: bge0

and the ifconfig of the Linux Box:

eth0.2    Link encap:Ethernet  HWaddr d8:d3:85:28:d3:28

          inet addr:10.0.0.2  Bcast:10.0.0.255  Mask:255.255.255.0
          inet6 addr: fe80::dad3:85ff:fe28:d328/64 Scope:Link
          inet6 addr: 2001:470:9b36:2::2/64 Scope:Global
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:962 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:43400 (42.3 KiB)

But i still not able to ping the VLANs from each side ? What would be the states of each of the interfaces bge0 and eth0 ?

NB: the eth0 and bge0 are up and running

I'm working on a supervision project based on OpenVPN, a good way to send some network traffic through a secure channel to office from there out to the Internet. On office i have an OpenVPN server installed and i need to monitor all branches servers that are behind firewalls. I know that the point to point solution is very easy so we may only install OpenVPN client on node that i need to monitor.
In the fact, is there any other issue that could help to supervise all branches DMZ network, without installing the client on each machines.

http://imagebin.ca/img/SWNToWz.jpg

I'm working on a network migration project as we will be moving our local office.

In the new building we have 5 floors with 50 employees in each one. I need 5 switches with at least 72 ports that support VLAN and STP and a switch layer 3 that will be in data center, and that will interconnect servers to others switches.

I need VLANs to be capable of full GigE-communication between ports, and at least 4 fiber ports as the link between the data center and floors is fiber.

We have an HP Procurve 5803xl switch that will be in the data center, but it's missing some GbE modules and also mini-GBIC modules for fiber Ethernet.

While looking for Ethernet switch with Gb support I came with some candidates SMC, Netgear, Nortel or may be others? Based on your experience what is the most stable of these switches? Also what would be the future topology for such network ?

How to enable SATA RAID on DL180G5 E5405, because i did not find any equivalent option on the BIOS, nor any prompt for that.

When you finished installation of your linux machine, what are the first packages that you install, and what are the tools that you get first ?

In my Debian box, I get pv, screen, ccze, ... like this

apt-get install pv screen ccze

After honeypots comes IBM's Billy Goat to lock horns with malicious coders.

So, is there any other approach to detect and collect potential attacks from malicious people?

What is your security plan against some kind of attacks? Why do many attackers find solutions to trap sysadmins?

Please offer your feedback.

There are a variety of ways to replace one string of text with another across many files. Here are a few ways:

using sed and find:

sed 's/oldstring/newstring/' "$1" > "$1".new && find -iname "*.new" | sed 's/.new//' | sh

using grep and sed:

grep -rl oldstring . | xargs sed -i -e 's/oldstring/newstring/'

using grep and perl:

grep -rl oldstring . | xargs perl -pi~ -e 's/oldstring/newstring/'

Please offer your own suggestions.

I have an HP StorageWorks (MSA 2012fc) and it has been used for production for a while. I used parted to set up three 0x83 partitions on it.
After a power off, my Linux box attached to the MSA via fiber channel become enable to see any partitions. And when i do dmesg i get that there are only a volume named as sda ?
Also, when i list the dev directory, there are only /dev/sda.
All partitions are absent, please can you explain what happened, and how can i restore the hole of my data.