*nix education & certification questions

[Jim Dennis]

On Tue, Jul 05, 2005 at 04:32:20PM -0700, Eric Wagar wrote:
>> 1) What would be the best certification path(s)? Do you think something
>> like a Solaris Sys Admin cert program or a Red Hat cert program would 
>> be best?
>> Or something more generic (CompTIA, SAIR, LPI?)? Granted, I would rather
>> LEARN the OS IN AND OUT, not just have some highly-regarded piece of paper.
 
> My *personal* experience has been with the RedHat RHC* series.  I am
> hoping to take mine sometime this year.  (Hoping because it will be on
> my own dime and with my own vacation time.)
 
> From what I have seen and read for the RHC* series, the tests are all
> hands-on practical tests.  (Same as the Cisco tests.)  I am a Sun
> Solaris 7 certified admin.  When the day comes that it has been of use
> to me, I will let you know!  :)  (It was all book knowledge, nothing
> real world.)
 
> I also have three highly skilled and knowledgeable co-workers who took
> the Redhat RHCE Bootcamp (the company paid) and they did not get the T
> or the E cert.  So, that tells me that I must study and then absorb
> *everything* in the classes I will be taking.
 
> Out of the Sun or RH cert, I'd take someone who had the RH cert.
> eric

 My comments:

    CompTIA Linux+ and related tests: 
        Not worth the paper they're printed on
    Sair:
        Are they *still around*?  (Yes, I know they are, but I'm still
        incredulous).
    LPIC:
        Their heart is in the right place; but I don't think any
        employers will notice this on your resume
    Novell SCLP (S.u.S.E. Certified Linux Professional):
        This shows some promise but it's too early to tell.
    RHCE:
        As  you say, this is all hands on.  I haven't taken this test
        yet, but I've had several students in my own (in-house) sysadmin
        classes who have attained RHCEs and my experience was that they
        were among my most knowlegeable students.  (They consistenly assure
        me that I will pass these with ease, given what they could see of my
        knowlege and skills from taking 5 days of my classes).

    Sun Certified Solaris:
        I've never had anyone express any interest in this.  The lack of
        this seems to have no effect on my resume --- but I am known
        primarily as a Linux guru; so any Solaris knowlege that leaks
        over is just gravy for the people interested in me.

 A co-worker of mine just took the RH bootcamp and test last week.  I
 suspect that he'll tell me how it went next week and I'll be talking
 to my manager to see if they want me to take the class or just
 challenge the test.  (Class+test: ~$3500, just the test: ~$800).
 Since they've had me teaching a whole serious of in-house classes in
 the hopes that many of my students would attain at least the RHCT
 the main benefit of running me through the class would be for me to
 observe the teaching style and ensure that I'm not missing anything
 major in my own courseware.

 My advice:

    Run Linux at home.  Get it running on at least two machines (client
    and server).  Configure one of the systems to be a kickstart server
    (installing and configuing DHCP, tftpd and httpd daemons, an NFS
    export, and DNS (with forward and reverse zones).  Make it a router
    and keep the client system on a separate segment "inside" the
    server/router.

    Tear apart a copy of the initrd (initial RAM disk) and read the
    /linuxrc you find therein.  Read the nash man page.  Start at the
    top of your /etc/inittab: for every line run the file command on the
    command in the third field.  If it's a binary, read the man page; 
    if it's a script, read it.  For every line in the rc.sysinit (and
    other start-up scripts) follow the same procedure.

    Run multiple kickstarts from CD, floppy, and over PXE.  Customize
    your kickstarts to run over NFS and HTTP, and write as much as you
    can into post installation and post upgrade scripts.  Install
    different versions.  Add the useradd commands to your kickstart
    to preserve your account info (include the -p to preserve your
    password hash).  Set the system up with GRUB passwords, MD5 encoded
    and in the kickstart.  So the same for LILO.  Configure inittab
    to run sulogin in single-user mode.

    Convert the client from using DHCP to static IPs.  Figure out how
    to bind the client's MAC address to a specific kickstart
    configuration.  Figure out how to have your client restore its
    static addressing information during a kickstart post-install.

    Peform an absolutely minimal installation.  Then try to install all
    of the packages necessary to get X and GNOME running properly.
    (Learn how to deal with RPM dependency hell).

    Configure the server to do masquerading.  Add squid.  Configure it
    to run squid as a transparent proxy, *and* to allow access to its
    own local httpd as well.

    Configure the server to be a NIS master.  Configure the client to be
    a NIS client.  Then convert them to both use LDAP.  Configure autofs
    on the client.

    Configure the server to provide mail services using sendmail and
    whatever POP and IMAP servers come with your copy of RH.  Configure
    fetchmail on the client.

    Install a webmail package on the server.  Access it with the client.

    Change video cards, add memory and add a disk drive to the client.
    Reconfigure the X, add a filesystems and mount points for the drive.
    (Notice that the additional memory generally needs no special
    configuration).

    Reconfigure the client system to use LVM.  Add the other drive as
    a PV to your VG.  Resize some of your partitions.  Figure out how
    to remove one PV from your VG while preserving all the data.  Learn
    how to access the VG from a generic rescue disc (like Ubuntu's live
    CD).

    Re-install the client using soft-RAID; use mirroring on the rootfs
    and RAID 5 for /home.  (Yes, get a small stack of cheap drives for
    this.  I'd recommand about 6 of them and you'll probably need an
    extra controller as well --- getting experience with SCSI, and USB
    storage is good).  Pull cables on different drives (with the system
    off) and power it back up.  Learn how to configure the system to
    boot off either mirror (CMOS settings *and* bootloader using both
    GRUB and LILO).  Learn how to restore the RAID sets (blank the drive
    you pulled .

    Pick out some of the .src RPMs.  Install and rebuild them.  Make
    minor packaging changes (for example build a custom version of the
    screen RPM that makes the screen binary setUID root and associated
    with some local "screen" group --- but not world executable; add the
    necessary groupadd command to the pre-install and the removal to the
    post install).  Be sure this rebuilt RPM has a distinctive name like:
    foo-1.2.3-MINE4.i486.rpm

    Write your own RPM from scratch.  Create a simple "service" that
    just does "logger hello world" in your rc scripts and a simple cron
    job that calls it periodically; build the RPM around that script
    and have the post-install do the necessary chkconfig --add and
    service commands.  Be sure that the pre-remove does the necessary
    chkconfig --del and service stop commands.

    To learn RHEL3 and RHEL4 consider playing with the community
    rebuilds of the same sources: CentOS: http://www.centos.org/
    Fetch CentOS3 and CentOS3.5 and CentOS4 and CentOS4.1.  Practice
    installing and upgrading; including kickstarts into 3.0 with
    post-install upgrades up to 3.5 (RHEL3 update 5) and so on.

    Burn your own CDs and DVDs.  Figure how to loop mount the .iso
    images that you download from centos.org and how to export those
    over NFS.

    Install and run Bastille (http://bastille-linux.org/ ). It will
    ask you all sorts of questions about how you want to use the system
    with all sorts of advice on securing it.  It will then use your
    responses to lock down the system.  Now tear apart every change
    it made and figure out how it worked and why each of those changes
    was made.  Figure out how to save and apply a Bastille policy as
    part of a kickstart post installation.

    Have a friend change your root password.  Break in and fix it.

    Configure your kickstart server to also serve "rescue" images
    for both RHEL4 and RHEL3 (to PXE boots).

    Have a friend break something else (give him or her a long list of 
    possibilities: netmask, default route, hostname, nsswitch.conf,
    /etc/pam.d configuration files, /etc/fstab, grub.conf or lilo.conf,
    filesystem labels, ...).  Diagnose and fix each of these in turn.
    Learn how to use rpm -qf and rpm -V effectively!
 
 In other words my advice is to set up your own lab (two or three cheap
 systems; the server can even be headless --- configure it for serial
 console and use a null modem cable).  Set up your own little self-study
 group (with one or a few others who are also interested in pursuing
 an RHCE).  Find creative ways to break the system for your partners to
 diagnose and repair and have them return the favor.  (Search google and 
 the newsgroups for problems that you can reproduce in your lab).

 Sorry I'm not available to teach external classes at this time.
 However, many of these are exactly the sorts of things I do in my
 classes.  (Unfortunately 5 days isn't long enough for most of these and
 I have about 25 hours of lecture materials to get through, too).

-- 
Jim Dennis