%jsonhash = (
    results => {
        single_key => {
            subnet_id  => undef,
            ...,
            certname   => 'adm003.siege.red',
            ...,
            realm_name => undef
        }
    },
    ...
);

##</code><code>##

%h = (r => { x => { a => 1, b => 2 }})

##</code><code>##

$ alias perld='perl -Mstrict -Mwarnings -MData::Dump -E'

##</code><code>##

$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd \%h'
{ r => { x => { a => 1, b => 2 } } }

##</code><code>##

$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd $h{r}'
{ x => { a => 1, b => 2 } }

##</code><code>##

$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd $h{r}{x}'
{ a => 1, b => 2 }

##</code><code>##

$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd $_ for values %{$h{r}}'
{ a => 1, b => 2 }

##</code><code>##

$ perlbrew switch perl-5.14.0t
$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd $_ for values $h{r}'
{ a => 1, b => 2 }

##</code><code>##

$ perlbrew switch perl-5.24.0t
$ perld 'my %h = (r => { x => { a => 1, b => 2 }}); dd $_ for values $h{r}->%*'
{ a => 1, b => 2 }

##</code><code>##

%{ $jsonhash{results}{single_key} }
$jsonhash{results}{single_key}->%*

##</code><code>##

$jsonhash{results}{single_key}{certname}