Guidance on new server imigration
Results 1 to 5 of 5
Like Tree1Likes
  • 1 Post By samgreco

Thread: Guidance on new server imigration

  1. #1
    Active Member
    Join Date
    Aug 2012
    Posts
    11

    Guidance on new server imigration

    I have been having all sorts of issues getting a new server setup using the same IP and hostname. Is there any guidance on this anywhere? Seems that I can never get DNS to resolve correctly on the new server with the adapter set to old IP address deactivated. What am I missing?

    Would it be better for me to build a server with a new hostname and IP and just do it that way? Can I do an incremental migration that way?

    I have used a week of the trial on the old server messing around with this. I need to get this moving

  2. #2
    ZeXtras Community Manager ZeXtras Employee Cine's Avatar
    Join Date
    Apr 2011
    Posts
    2,342
    Hello samgreco!

    The Incremental Migration's sole requirement is to have ZeXtras Suite installed on both the source and destination server. Just like any other ZeXtras migration is completely unaffected by OS, Architecture and Network Configuration for the two servers.

    Thus said, setting up the new server with a different IP address is the easiest way to go.
    The hostname can be the same as you can force the name resolution through bind/dnsmasq (Zimbra's official setup guide treats Bind, I prefer DNSMasq).

    DNSMasq Configuration example:
    192.168.0.2 is the LAN ip of your new server
    mail.domain.com is the hostname of the server
    domain.com is the main mail domain
    domain2.com is an additional mail domain
    8.8.8.8 and 8.8.4.4 are the "real" DNS servers you want to use (in this case, Google's)

    /etc/resolv.conf
    Code:
    nameserver 192.168.0.2
    DNSMasq will bind on the local address to answer DNS queries.

    /etc/resolv.dnsmasq
    Code:
    nameserver 8.8.8.8
    nameserver 8.8.4.4
    We'll instruct DNSMasq to answer just some queries and in the way we want, while all other queries will be forwarded to this servers.

    /etc/dnsmasq.conf (the file is quite large, I'll only write the config elements relevant to this guide)
    Code:
    address=/mail.domain.com/192.168.0.2
    resolv-file=/etc/resolv.dnsmasq
    except-interface=lo
    listen-address=192.168.0.2
    bind-interfaces
    This sets up DNSMasq to listen on the local IP address and to only bind on the interface it's listening on. Also, it forces to answer any A-record DNS requests for mail.domain.com with the LAN ip. This is a "naive" trick that allows you to provisionally use the same hostname on two servers without any issues of sort.

    In the same file, add one line like the following for each domain on your server:
    Code:
    mx-host=domain.com,mail.domain.com,10
    This lines instruct DNSMasq to always return "mail.domain.com" as the MX record for your domains which, if your /etc/hosts file is correctly configured, will always point to the local server (DNSMasq will then forward any other request to the DNS servers in the resolv.dnsmasq file).

    Restart DNSMasq with
    Code:
    /etc/init.d/dnsmasq restart
    and check that
    Code:
    dig mx domain.com
    returns the local hostname/address.

    Also check that other DNS queries are correctly managed through the "real" dns servers.


    In order to further guide you I'd like to have some more informations about your setup:

    - Standard or Multiserver?
    - Source server's OS, Arch and Zimbra version
    - Source and destination server storage type?
    - What is the networking design? (e.g. servers in the same LAN with a firewall forwadring traffic from the outside, servers in the DMZ, servers in geographically different networks etc...)

    Have a nice day,
    Cine
    the ZeXtras Team
    IT Support Team Contact Form
    Sales Team Contact Form

    ZeXtras Website
    # ZeXtras Wiki # ZeXtras Store

    Have ZeXtras Suite or ZeXtras Migration Tool been helpful to you?
    Share your experience in the Zimbra Gallery!

    ZeXtras Suite on the Zimbra Gallery
    ZeXtras Migration Tool on the Zimbra Gallery

  3. #3
    Active Member
    Join Date
    Aug 2012
    Posts
    11
    Wow. Incredibly comprehensive answer Thank you.

    To answer your questions:
    Both servers are VMs in VMWare Server (yes, I know)
    Source:
    Standard Server
    Centos 5.3- 32-bit - Zimbra 7.2.2
    Storage: LVM (one large)
    Destination
    Standard Server
    Ubuntu 12.04LTS 64-bit - Zimbra 8.0.2
    Storage: LVM (one large)

    Network is behind a firewall. I have multiple IP addresses from the outside forwarding through the firewall to various servers. NONE are in the DMZ. My firewall is a Netgear Prosafe, which unfortunately, does not have VLAN capability.

    A question about your scenario above: Would I still use BIND with DNSMASQ?

  4. #4
    ZeXtras Community Manager ZeXtras Employee Cine's Avatar
    Join Date
    Apr 2011
    Posts
    2,342
    Quote Originally Posted by samgreco View Post
    Wow. Incredibly comprehensive answer Thank you.
    You're welcome!

    Quote Originally Posted by samgreco View Post
    To answer your questions:
    Both servers are VMs in VMWare Server (yes, I know)
    Source:
    Standard Server
    Centos 5.3- 32-bit - Zimbra 7.2.2
    Storage: LVM (one large)
    Destination
    Standard Server
    Ubuntu 12.04LTS 64-bit - Zimbra 8.0.2
    Storage: LVM (one large)

    Network is behind a firewall. I have multiple IP addresses from the outside forwarding through the firewall to various servers. NONE are in the DMZ. My firewall is a Netgear Prosafe, which unfortunately, does not have VLAN capability.
    This is one of the "easiest" scenarios... You only need to setup the destination server with the same hostname and a different LAN ip, migrate your data as described in the Incremental Migration guide and then simply change your Firewall's config so that it will forward traffic from the outside to the new server instead of the old one and your internal DNS server (if any) so that clients inside the LAN resolve the hostname with the new IP...

    Quote Originally Posted by samgreco View Post
    A question about your scenario above: Would I still use BIND with DNSMASQ?
    Not really... Bind and DNSMasq perform the very same task so using one of them is enough... Feel free to use Bind if you are more familiar with it, the concept is to make sure that the local IP is returned when the server queries for the MX record of one of its domains and also when it queries for the A record of the public hostname for each domain.


    Feel free to ask any question you might have before and during the migration!

    Have a nice day,
    Cine
    IT Support Team Contact Form
    Sales Team Contact Form

    ZeXtras Website
    # ZeXtras Wiki # ZeXtras Store

    Have ZeXtras Suite or ZeXtras Migration Tool been helpful to you?
    Share your experience in the Zimbra Gallery!

    ZeXtras Suite on the Zimbra Gallery
    ZeXtras Migration Tool on the Zimbra Gallery

  5. #5
    Active Member
    Join Date
    Aug 2012
    Posts
    11
    THANK YOU, Thank You, Thank You! I LOVE dnsmasq! So much easier than BIND to get things right. And it looks like it will be very easy to update when needed. One line for an MX record. Nice.

    So everything installed well. I will now try and get the migration rolling.
    d0s0n likes this.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •