RE: Dynamic server management?
Hi Thomas, In the scenario you describe, 1 and 2 won't make any progress as they are not part of a component that contains a quorum (a majority in this current implementation). Servers 3,4,5 will elect a leader (if they don't have one yet), and will make progress independently. Once the segmentation heals, 1 and 2 will synchronize with the current leader. Thanks, -Flavio > -Original Message- > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > Sent: Monday, November 17, 2008 2:04 PM > To: zookeeper-user@hadoop.apache.org > Subject: AW: Dynamic server management? > > Hi Flavio, > > Thank you for the information. > > So how do you handle than the following scenario? > You have 5 servers and temporary network segmentation, where server 1 and > 2 cannot talk to 3,4 and 5. Will server 1 and 2 do a new leader election > for their partition, as well server 3,4 and 5 for their partition? If yes, > how do they synchronize if they can reach each other again? > > > Mit freundlichen Grüßen / With best regards > Thomas Kießlich > > Siemens Enterprise Communications GmbH & Co. KG > HiPath Applications > > SEN LIP DA 11 > Schertlinstr. 8 > 81379 Munich, Germany > > -Ursprüngliche Nachricht- > Von: Flavio Junqueira [mailto:[EMAIL PROTECTED] > Gesendet: Montag, 17. November 2008 13:49 > An: zookeeper-user@hadoop.apache.org > Betreff: RE: Dynamic server management? > > Hi Thomas, We currently don't have such a feature of adding and removing > servers dynamically, although we would like to, so we'll have it > eventually. > > Without a dynamic mechanism for adding and removing servers, your example > is > problematic. Suppose that you configure your ensemble to have 3 servers, > and > then you start only one. Your single server would say: "Hey, I'm alone so > I > should make progress independently". This is reasonable, right? Well, not > really, because you can have the following alternative execution. You > start > your three servers, but there is a temporary network partition and server > 1 > cannot talk to servers 2 and 3. Consequently, server 1 will make progress > independently of 2 and 3, and their state will diverge. > > Hope it helps. > > -Flavio > > > -Original Message- > > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > > Sent: Monday, November 17, 2008 11:46 AM > > To: zookeeper-user@hadoop.apache.org > > Subject: Dynamic server management? > > > > Hi all, > > > > I am evaluating ZooKeeper as a discovery protocol. I want to change the > > number of servers that build up ensemble during runtime of an existing > > number servers. Is that possible or do I have to change the > configuration > > and restart all servers? I found that if you have 3 servers configured > and > > startup the first it is continously looking for the at least one other > > server. Is it really necessary to do that? If the first server does not > > find anyone else, it could elect itself as the leader. If the next > server > > starts up the can redo the election I guess. > > Could you please help me with these questions? Thank you. > > > > > > > > Mit freundlichen Grüßen / With best regards > > Thomas Kießlich > > > > Siemens Enterprise Communications GmbH & Co. KG > > HiPath Applications > > > > SEN LIP DA 11 > > Schertlinstr. 8 > > 81379 Munich, Germany > > > > Phone: +49 (89) 722-32483 > > Fax: +49 (89) 722-40560 > > Email: [EMAIL PROTECTED] > > > > Communication for the open minded > > www.siemens.de/open > > www.siemens.com/open > > > > Siemens Enterprise Communications GmbH & Co. KG > > Managing Directors: Andreas Bernhardt, Reinhard Benditte, > > Gerhard Otterbach, Thomas Zimmermann > > Registered offices: Munich > > Commercial registry Munich, HRA 88546 > > WEEE-Reg.-No. DE 27980375 > > General Partner: > > Siemens Enterprise Communications Management GmbH > > Registered offices: Munich > > Commercial registry: Munich, HRB 163415 > > > > Wichtiger Hinweis: Diese Information ist für den Gebrauch durch die > Person > > oder die Firma/Organisation bestimmt, die in der Empfängeradresse > benannt > > ist. Wenn Sie nicht der angegebene Empfänger sind, nehmen Sie bitte zur > > Kenntnis, daß Weitergabe, Kopieren, Verteilung oder Nutzung des Inhalts > > dieser Email-Übertragung unzulässig ist. Falls Sie diese Email > irrtümlich > > erhalten haben, benachrichtigen Sie den Absender bitte unverzüglich > > telefonisch oder durch eine Email. Vielen Dank. > > > > Important Note: This e-mail may contain trade secrets or privileged, > > undisclosed or otherwise confidential information. If you have received > > this e-mail in error, you are hereby notified that any review, copying > or > > distribution of it is strictly prohibited. Please inform us immediately > > and destroy the original transmittal. Thank you for your cooperation. > > >
AW: Dynamic server management?
Hi Flavio, Thank you for the information. So how do you handle than the following scenario? You have 5 servers and temporary network segmentation, where server 1 and 2 cannot talk to 3,4 and 5. Will server 1 and 2 do a new leader election for their partition, as well server 3,4 and 5 for their partition? If yes, how do they synchronize if they can reach each other again? Mit freundlichen Grüßen / With best regards Thomas Kießlich Siemens Enterprise Communications GmbH & Co. KG HiPath Applications SEN LIP DA 11 Schertlinstr. 8 81379 Munich, Germany -Ursprüngliche Nachricht- Von: Flavio Junqueira [mailto:[EMAIL PROTECTED] Gesendet: Montag, 17. November 2008 13:49 An: zookeeper-user@hadoop.apache.org Betreff: RE: Dynamic server management? Hi Thomas, We currently don't have such a feature of adding and removing servers dynamically, although we would like to, so we'll have it eventually. Without a dynamic mechanism for adding and removing servers, your example is problematic. Suppose that you configure your ensemble to have 3 servers, and then you start only one. Your single server would say: "Hey, I'm alone so I should make progress independently". This is reasonable, right? Well, not really, because you can have the following alternative execution. You start your three servers, but there is a temporary network partition and server 1 cannot talk to servers 2 and 3. Consequently, server 1 will make progress independently of 2 and 3, and their state will diverge. Hope it helps. -Flavio > -Original Message- > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > Sent: Monday, November 17, 2008 11:46 AM > To: zookeeper-user@hadoop.apache.org > Subject: Dynamic server management? > > Hi all, > > I am evaluating ZooKeeper as a discovery protocol. I want to change the > number of servers that build up ensemble during runtime of an existing > number servers. Is that possible or do I have to change the configuration > and restart all servers? I found that if you have 3 servers configured and > startup the first it is continously looking for the at least one other > server. Is it really necessary to do that? If the first server does not > find anyone else, it could elect itself as the leader. If the next server > starts up the can redo the election I guess. > Could you please help me with these questions? Thank you. > > > > Mit freundlichen Grüßen / With best regards > Thomas Kießlich > > Siemens Enterprise Communications GmbH & Co. KG > HiPath Applications > > SEN LIP DA 11 > Schertlinstr. 8 > 81379 Munich, Germany > > Phone: +49 (89) 722-32483 > Fax: +49 (89) 722-40560 > Email: [EMAIL PROTECTED] > > Communication for the open minded > www.siemens.de/open > www.siemens.com/open > > Siemens Enterprise Communications GmbH & Co. KG > Managing Directors: Andreas Bernhardt, Reinhard Benditte, > Gerhard Otterbach, Thomas Zimmermann > Registered offices: Munich > Commercial registry Munich, HRA 88546 > WEEE-Reg.-No. DE 27980375 > General Partner: > Siemens Enterprise Communications Management GmbH > Registered offices: Munich > Commercial registry: Munich, HRB 163415 > > Wichtiger Hinweis: Diese Information ist für den Gebrauch durch die Person > oder die Firma/Organisation bestimmt, die in der Empfängeradresse benannt > ist. Wenn Sie nicht der angegebene Empfänger sind, nehmen Sie bitte zur > Kenntnis, daß Weitergabe, Kopieren, Verteilung oder Nutzung des Inhalts > dieser Email-Übertragung unzulässig ist. Falls Sie diese Email irrtümlich > erhalten haben, benachrichtigen Sie den Absender bitte unverzüglich > telefonisch oder durch eine Email. Vielen Dank. > > Important Note: This e-mail may contain trade secrets or privileged, > undisclosed or otherwise confidential information. If you have received > this e-mail in error, you are hereby notified that any review, copying or > distribution of it is strictly prohibited. Please inform us immediately > and destroy the original transmittal. Thank you for your cooperation. >
RE: Dynamic server management?
Hi Thomas, We currently don't have such a feature of adding and removing servers dynamically, although we would like to, so we'll have it eventually. Without a dynamic mechanism for adding and removing servers, your example is problematic. Suppose that you configure your ensemble to have 3 servers, and then you start only one. Your single server would say: "Hey, I'm alone so I should make progress independently". This is reasonable, right? Well, not really, because you can have the following alternative execution. You start your three servers, but there is a temporary network partition and server 1 cannot talk to servers 2 and 3. Consequently, server 1 will make progress independently of 2 and 3, and their state will diverge. Hope it helps. -Flavio > -Original Message- > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > Sent: Monday, November 17, 2008 11:46 AM > To: zookeeper-user@hadoop.apache.org > Subject: Dynamic server management? > > Hi all, > > I am evaluating ZooKeeper as a discovery protocol. I want to change the > number of servers that build up ensemble during runtime of an existing > number servers. Is that possible or do I have to change the configuration > and restart all servers? I found that if you have 3 servers configured and > startup the first it is continously looking for the at least one other > server. Is it really necessary to do that? If the first server does not > find anyone else, it could elect itself as the leader. If the next server > starts up the can redo the election I guess. > Could you please help me with these questions? Thank you. > > > > Mit freundlichen Grüßen / With best regards > Thomas Kießlich > > Siemens Enterprise Communications GmbH & Co. KG > HiPath Applications > > SEN LIP DA 11 > Schertlinstr. 8 > 81379 Munich, Germany > > Phone: +49 (89) 722-32483 > Fax: +49 (89) 722-40560 > Email: [EMAIL PROTECTED] > > Communication for the open minded > www.siemens.de/open > www.siemens.com/open > > Siemens Enterprise Communications GmbH & Co. KG > Managing Directors: Andreas Bernhardt, Reinhard Benditte, > Gerhard Otterbach, Thomas Zimmermann > Registered offices: Munich > Commercial registry Munich, HRA 88546 > WEEE-Reg.-No. DE 27980375 > General Partner: > Siemens Enterprise Communications Management GmbH > Registered offices: Munich > Commercial registry: Munich, HRB 163415 > > Wichtiger Hinweis: Diese Information ist für den Gebrauch durch die Person > oder die Firma/Organisation bestimmt, die in der Empfängeradresse benannt > ist. Wenn Sie nicht der angegebene Empfänger sind, nehmen Sie bitte zur > Kenntnis, daß Weitergabe, Kopieren, Verteilung oder Nutzung des Inhalts > dieser Email-Übertragung unzulässig ist. Falls Sie diese Email irrtümlich > erhalten haben, benachrichtigen Sie den Absender bitte unverzüglich > telefonisch oder durch eine Email. Vielen Dank. > > Important Note: This e-mail may contain trade secrets or privileged, > undisclosed or otherwise confidential information. If you have received > this e-mail in error, you are hereby notified that any review, copying or > distribution of it is strictly prohibited. Please inform us immediately > and destroy the original transmittal. Thank you for your cooperation. >
Dynamic server management?
Hi all, I am evaluating ZooKeeper as a discovery protocol. I want to change the number of servers that build up ensemble during runtime of an existing number servers. Is that possible or do I have to change the configuration and restart all servers? I found that if you have 3 servers configured and startup the first it is continously looking for the at least one other server. Is it really necessary to do that? If the first server does not find anyone else, it could elect itself as the leader. If the next server starts up the can redo the election I guess. Could you please help me with these questions? Thank you. Mit freundlichen Grüßen / With best regards Thomas Kießlich Siemens Enterprise Communications GmbH & Co. KG HiPath Applications SEN LIP DA 11 Schertlinstr. 8 81379 Munich, Germany Phone: +49 (89) 722-32483 Fax: +49 (89) 722-40560 Email: [EMAIL PROTECTED] Communication for the open minded www.siemens.de/open www.siemens.com/open Siemens Enterprise Communications GmbH & Co. KG Managing Directors: Andreas Bernhardt, Reinhard Benditte, Gerhard Otterbach, Thomas Zimmermann Registered offices: Munich Commercial registry Munich, HRA 88546 WEEE-Reg.-No. DE 27980375 General Partner: Siemens Enterprise Communications Management GmbH Registered offices: Munich Commercial registry: Munich, HRB 163415 Wichtiger Hinweis: Diese Information ist für den Gebrauch durch die Person oder die Firma/Organisation bestimmt, die in der Empfängeradresse benannt ist. Wenn Sie nicht der angegebene Empfänger sind, nehmen Sie bitte zur Kenntnis, daß Weitergabe, Kopieren, Verteilung oder Nutzung des Inhalts dieser Email-Übertragung unzulässig ist. Falls Sie diese Email irrtümlich erhalten haben, benachrichtigen Sie den Absender bitte unverzüglich telefonisch oder durch eine Email. Vielen Dank. Important Note: This e-mail may contain trade secrets or privileged, undisclosed or otherwise confidential information. If you have received this e-mail in error, you are hereby notified that any review, copying or distribution of it is strictly prohibited. Please inform us immediately and destroy the original transmittal. Thank you for your cooperation.
