RE: [TESTDAY] xl restore gives an error too soon after xl save

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: George Dunlap <George.Dunlap@xxxxxxxxxx>
> Sent: 09 June 2020 17:45
> To: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>
> Cc: Paul Durrant <paul@xxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Wei 
> Liu <wl@xxxxxxx>; Anthony
> Perard <anthony.perard@xxxxxxxxxx>
> Subject: [TESTDAY] xl restore gives an error too soon after xl save
> 
> Somewhat surprising that if you save with -D, you get mysterious error 
> messages for the next so-many
> seconds:
> 
> root@immortal:/images# xl save -D c6-01 /images/tmp/c6-01.save
> Saving to /images/tmp/c6-01.save new xl format (info 0x3/0x0/950)
> xc: info: Saving domain 19505, type x86 PV
> xc: Frames: 524288/524288  100%
> xc: End of stream: 0/0    0%
> root@immortal:/images# xl restore tmp/c6-01.save
> Loading new save file tmp/c6-01.save (new xl fmt info 0x3/0x0/950)
>  Savefile contains xl domain config in JSON format
> Parsing config from <saved>
> libxl: error: libxl_create.c:692:libxl__domain_make: Domain 19505:domain id 
> recently used: No such
> file or directory
> libxl: error: libxl_create.c:1233:initiate_domain_create: Domain 19505:cannot 
> make domain: -3
> libxl: error: libxl_domain.c:1182:libxl__destroy_domid: Domain 
> 19505:Non-existant domain
> libxl: error: libxl_domain.c:1136:domain_destroy_callback: Domain 
> 19505:Unable to destroy guest
> libxl: error: libxl_domain.c:1063:domain_destroy_cb: Domain 19505:Destruction 
> of domain failed
> root@immortal:/images# xl restore tmp/c6-01.save
> Loading new save file tmp/c6-01.save (new xl fmt info 0x3/0x0/950)
>  Savefile contains xl domain config in JSON format
> Parsing config from <saved>
> libxl: error: libxl_create.c:692:libxl__domain_make: Domain 19505:domain id 
> recently used: No such
> file or directory
> libxl: error: libxl_create.c:1233:initiate_domain_create: Domain 19505:cannot 
> make domain: -3
> libxl: error: libxl_domain.c:1182:libxl__destroy_domid: Domain 
> 19505:Non-existant domain
> libxl: error: libxl_domain.c:1136:domain_destroy_callback: Domain 
> 19505:Unable to destroy guest
> libxl: error: libxl_domain.c:1063:domain_destroy_cb: Domain 19505:Destruction 
> of domain failed
> 
> [A few minutes pass]
> 

Yes, this is because it is not 'safe' to re-create the domain with the same 
domid until it is deemed not 'recently used'. This
should indeed be documented.

  Paul

> root@immortal:/images# xl restore tmp/c6-01.save
> Loading new save file tmp/c6-01.save (new xl fmt info 0x3/0x0/950)
>  Savefile contains xl domain config in JSON format
> Parsing config from <saved>
> xc: info: Found x86 PV domain from Xen 4.14
> xc: info: Restoring domain
> xc: info: Restore successful
> xc: info: XenStore: mfn 0xbe8d2, dom 0, evt 1
> xc: info: Console: mfn 0xbe8d1, dom 0, evt 2